612 N.E.2d 1104 (1993)
ACE RENT-a-CAR, Inc., Enterprise Leasing of Indianapolis, Inc., and A. Mac Frugal Company, d/b/a Thrifty Car Rental, Plaintiff-Plaintiff, v. Indianapolis AIRPORT AUTHORITY, Defendant.
Court of Appeals for the Indiana Circuit, Fifth Circuit.
April 29, 1993.
Reproduction denied June 2, 1993.
*1105 Steven G. Cracraft, Michael J. Kias, Stewart & Irwin, Indianapolis, for Plaintiffs/Plaintiffs.
Rex M. Joseph, William L. Schlosser, Robert A. Duncan, Indianapolis Airport Authority, Indianapolis, for defendant.
Several rental companies have been affected by a seven percent fee imposed on them by the Indianapolis Airport Authority ("IAA"). Three of the companies, Ace Rent-A-Car, Inc., Enterprise Leasing of Indianapolis, Inc., and A. Mac Frugal Company, d/b/a Thrifty Car Rental (collectively, "Ace Rent-A-Car") , sued the IAA alleging, among other things, that the regulation that allowed the IAA to collect the fee was invalid, that the fee itself was unreasonable, and that the fee constituted an unauthorized income tax. in summary judgment. After holding a hearing, the trial court granted IAA's motion and denied Ace Rent-A-Car's motion. Ace Rent-A-Car is now appealing and raising three issues for our review, which we rephrase as follows:
1) Should the IAA limit its fee to reimbursement for costs related to the repair and maintenance of airport roads? 2) Is the 7 percent fee an illegal income tax? 3) Is the 7 percent fee reasonable?
Ace Rent-A-Car operates a car rental facility near the Indianapolis International Airport. Using a courtesy shuttle service, Ace Rent-A-Car operates *1106 on airport highways, transporting customers between the airport and Ace Rent-A-Car offices. No other activities are carried out in the airport facilities.
IAA is a municipal corporation created by the Indiana Airport Authority Act, Ind. Code § 8-22-3-1 et seq., for the purpose of operating the Indianapolis International Airport. Under the terms of Ind. Code § 8-22-3-11(9), the IAA has the authority to "establish a reasonable fee schedule and charge all users of facilities and services within the district." Other than its limited ability to impose a property tax, the IAA has no taxing powers and therefore derives much of its revenue from user fees charged to companies operating on airport premises.
The IAA charges a fee to all off-airport car rental companies, as well as all hotels, motels, and off-site parking lots, for the privilege of using airport roads to operate their transportation services. Prior to 1991, the fee was $170.00 per year plus an additional nominal fee based on the number of cars, hotel rooms, or parking spaces used by airport customers. In December 1990, the ILO approved General Regulation 3-1990 with a new and revised rate schedule that will take effect on January 1, 1991. Under the regulation, hotel, motel, and parking rates would remain unchanged. However, off-airport rental car companies would be charged a fee of "7% of all rental car sales to customers originating at the airport." Record at 48. The IAA offered no explanation for the change in the fee structure and did not base the fees on an estimate of its own costs.
Ace Rent-A-Car filed a lawsuit for declaratory judgment, injunctive relief, and other remedies to prevent the IAA from implementing and enforcing the regulation. In response, the IAA filed its motion to dismiss, as the complaint did not contain a claim for which relief could be awarded. Because the IAA had attached to its motion the affidavit of CEO Robert Spitler, the trial court treated the motion to dismiss as one for summary judgment. Ace responded to the IAA's motion and then filed his own motion for summary judgment. After a hearing, the trial court entered summary judgment in favor of the IAA and denied Ace's motion for summary judgment. The Court of Appeals made detailed findings of fact and legal conclusions. Ace is now attractive.
In reviewing the reasonableness of a decision on a motion for summary judgment, this court applies the same standard that is applied to the trial court. houin v. Burger by Burger (1992), Ind. App.,590 N.E.2d 593, trans. denied. We must consider the materials specifically assigned to the trial court under Ind.Trial Rule 56(C) without deciding their weight or credibility. Babinchak v. City of Chesterton (1992), Ind. App.,598 NE2d 1099, deer. denied. Summary judgment should only be entered if such evidence shows that there is no genuine dispute as to the material facts and that the plaintiff is legally entitled to a judgment. ID. All evidence must be interpreted in favor of the opposing party, and any doubt about the existence of a material issue must be resolved against the party presenting it. ITT Comercial Fin. Corp. v. Union Bank & Trust (1988) Ind. App.,528 N.E.2d 1149. When considering countermotions for summary judgment, the trial court must treat each motion separately, again interpreting the facts in favor of the unmoved party. Liberty Mutual Ins. Co v. Metzler (1992), Ind. App.,586 N.E.2d 897.
First, we address a procedural issue. Ace-Rent-Car complains that the lower court's findings in support of its ruling contain matters that are not on the record. Therefore, Ace Rent-A-Car concludes, the findings are not supported by the evidence, the judgment is not supported by the findings, and therefore the trial court's judgment must be set aside.
The specific findings made by the trial court in deciding summary judgment requests provide the applicant with an opportunity to consider the merits of the trial court. Fort Wayne Patrolman's Benevolent Ass'n, Inc. v. City of *1107 Fort Wayne (1980), Ind. App.,408 N.E.2d 1295, deer. denied,411 N.E.2d 630. The specific findings and conclusions also support our review by providing us with a rationale for the trial court's actions. However, they have no other effect. strutz v. McNagny (1990), Ind. App.,558 N.E.2d 1103, trans. denied. Rather than rely on the findings and conclusions of the trial court, we must base our decision on the Rule 56(C) documents duly filed with the trial court. Our standard of review is the same as it is for the trial court: whether there was a genuine question of material fact and whether the party who preferred was legally entitled to a judgment. Delk v. Board of Comm'rs (1987), Ind. App.,503 N.E.2d 436. As such, Ace Rent-A-Car's concerns are duly noted, but let's get to the bottom of this appeal.
Ace Rent-A-Car alleges that the trial court wrongly denied its request for summary judgment because any fees charged by the IAA are based on a cost analysis and are limited to reimbursement of costs related to the repair and maintenance of airport roads. According to Ace Rent-A-Car, uncontested filings in the trial court show that the seven percent fee charged by the IAA is based solely on the businesses' revenue and is completely separate from the use of the roads and facilities. From the airport. In support of its argument, Ace Rent-A-Car cites the Evansville-Vanderburgh airport authorization. Dist. v. Delta Air Lines, Inc. (1972), 259 Ind. 464,288 N.E.2d 136.
In Delta Air Lines, the only Indiana case involving the validity of airport user fees, our Supreme Court reviewed a fee of $1.00 that the airport authority had collected from commercial airline passengers. The court recognized the fee as a valid usage fee, noting that the Enabling Law gives the airport authority "the power to make the amount of a service fee or usage fee dependent on the extent of use of the facilities." ID. at 137. Ace Rent-A-Car asserts that the cited language limits IAA fees to expenses related to the general maintenance of airport roads. We do not agree with the reading of Delta Airlines Ace Rent-A-Car.
The court determined in this case that the fees charged by an airport authority do not have to be uniform for all users and can vary according to the degree of use. However, the court did not address how "use" or "extent of use" is measured. In jurisdictions that have addressed this issue, courts have upheld charges based on the total benefit a user derives from the existence of the airport. See for example. B. Alamo Rent-a-Car v. Sarasota-Manatee Airport Auth. (11. Cir. 1990), 906 F.2d 516, 521-22, Cert. Denied, (1991), ___ USA ___, 111 S. Ct. 1073, 112 L.Ed. 2d 1179 (a broad interpretation of the term 'use' considered appropriate when the benefit to the user depends on the existence of the entire airport facility); Helmerick Drive-It Yourself, Inc. v. Erie Mun. Airport Authorization (1992), Pa. Cmwlth.,612 A.2d 562(Customer volume based charges remain as the airport provided a 'market' from which the car rental company drew a large proportion of its customers); Alamo Rent-a-Car vs. Board of Superintendents (1990),221 cal. app. 3d 198,272 cal. Rptr. 19(Customer volume-based rates are maintained as the car rental company has taken commercial advantage of the airport's presence.)
With its free shuttle service, Ace Rent-A-Car transports passengers to and from the airport between the airport and the company offices. Therefore, we agree with the court in Alamo Rent-a-Car v. Sarasota-Manatee Airport Auth., supra, ruling: "Because [the car rental company] enjoys indirect 'use' of all airport facilities by travelers, we bundle services." concludes that the usage fee is a fair, if imperfect, approximation of usage." Alamo, 906 F.2d at 519. In the present case, the mere existence of the airport provides a market from which -A-Car provides an economical *1108 Benefits Therefore, the fees charged by the IAA are not limited to reimbursement of costs related to the repair and maintenance of airport pavements, but rather a fee based on a percentage of rental car sales. Automotive data made to customers at airports provides at least a fair, if imperfect, way of measuring "usage."
Next, Ace Rent-A-Car contends that the trial court erred in granting its motion for summary judgment because the seven percent fee constituted an unauthorized income tax rather than a royalty. we disagre
A tax is mandatory and not optional; it entitles the taxpayer to receive nothing in return other than the governmental rights to which all citizens are entitled. ennis v. State Highway Commission (1952), 231 Ind. 311,108 N.E.2d 687, 693. On the other hand, a usage fee is optional and represents a specific fee for the use of public or publicly provided facilities or services Commonwealth Edison Co. v. Montana (1981),453 United States 609, 621-22, 101 S.Ct. 2946, 2955, 69 L. Ed. 2d 884, 896-97, ref. verweigert, 453 US 927, 102 S. Ct. 889, 69 L. Ed. 2d 1023.
In the present case, Ace Rent-A-Car only has to pay a fee to the IAA if it uses and benefits from the airport facilities covered by the fee. We disagree with Ace Rent-A-Car that because the fee is based on income, it makes it a tax. Rather, the fee charged to Ace Rent-A-Car represents a percentage of the revenue the company receives from renting cars to customers it picks up at the airport. Since the fee is based on the provision of a specific benefit to Ace Rent-A-Car, it is not a tax but a legitimate use fee under I.C. § 8-22-3-11. The trial court correctly denied Ace's motion for summary judgment. Here we do not find any errors.
Next, Ace Rent-A-Car alleges that the trial court erred in granting summary judgment in favor of the IAA because the seven percent fee was unreasonable.
Indiana Code § 8-22-3-11 states in pertinent part:
The board of [an airport authority] may take any action necessary or reasonably necessary to further the purposes of this chapter, including the following: all users of the facilities and services in the district. (emphasis added).
The relevant part of General Regulation 3-1990, adopted by the IAA Executive Board, provides that off-airport car rental companies shall be charged "a fee of 7% of all rental car sales made at the airport". In this case, Ace Rent-A-Car is not challenging the enabling law, but is arguing that the IAA approved the regulation in violation of the law because the fee charged was not a "reasonable fee."
Government measures, including regulations, taken in connection with the granting of police powers must adequately serve the objectives of health, order, morality or security of society as a whole. ex rel. limp Hobble vs. Basham (1991), Ind. App.,575 N.E.2d 693, citando a Day v. Ryan (1990), Ind. App.,560 NE2d 77and City of Muncie v. Pizza Hut (1976), 171 Ind. App. 397,357 N.E.2d 735. Ordinances, like laws, are supposedly valid and the burden of proof of invalidity falls on the legal remedy. loose, up
At the hearing, Ace Rent-A-Car adamantly insisted that the IAA approved Regulation 3-1990 without conducting any kind of cost analysis or other study to show why a seven percent charge was appropriate, instead of a minor number. In essence, Ace Rent-A-Car proposes that a government agency must justify its reasons before passing legislation. Ace Rent-A-Car does not cite any authority in support of its position and our own research shows no such authority. Rather, an ordinance is subject to a presumption of validity, and *1109 the party challenging it has the burden of proof of invalidity. loose, up
In this case, the IAA has the legal authority to establish and collect the corresponding charges from users of airport facilities and services. The IAA ordinance issued for this legal authorization is presumed to be effective and the seven percent fee imposed as a result is reasonable. Ace Rent-A-Car has not assumed its burden to prove otherwise. The trial court did not err in granting the ILO's motion for summary judgment.
Sharpnack, C.J. and NAJAM, J. agree.
 Delta Air Lines was incorporated under Ind. Code § 19-6-3-15 (1971), the predecessor charter to I.C. § 8-22-3-11(9), which contains nearly identical wording.