FAA defines an FBO as a business granted the right by the airport to operate fueling facilities, hangars, aircraft tie-downs, aircraft rental, aircraft maintenance, flight instruction, and other aeronautical services at an airport. In addition, FBOs sometimes manage parking ramps for transient aircraft at the airport. FBOs may charge a fee for parking, as they also maintain the ramp areas for the airport. According to FAA, airports, within certain parameters, have the ability to charge or not to charge users for access to airport ramp space. FBOs generally serve pilots who operate general aviation aircraft, but can also support commercial flights. The type of amenities and services any one FBO provides varies. For example, representatives of one FBO said that it provides high-level customer service and offers more services such as catering, pilot lounges, concierge services, and aircraft maintenance and repair facilities for its clients. See figure 1 for an illustration of FBO services. As of March 2019, we identified 3,070 FBOs operating at 3,016 airports located in the contiguous United States; these airports are included in FAA’s National Plan of Integrated Airport Systems (NPIAS). FBOs can be run by the airport, an independent operator, or a network chain with multiple locations. The Transportation Research Board estimated in 2016 that 47 percent of all FBO locations were airport-operated. Most stakeholders with whom we spoke agreed that there are fewer FBOs today than in the past, although estimates vary on the extent of the decline in FBO numbers. Stakeholders we interviewed said that this decline is due to factors such as a drop in general aviation activity that resulted in a reduction in fuel sales. More recent innovations, such as more fuel-efficient aircraft and decision-making software that provides information to pilots on where to purchase fuel to fly more efficiently, also contributed to the decline. Airports that receive federal AIP grants contractually agree to FAA “grant assurances” that require those airports to adhere to certain requirements. One of those key grant assurances is a prohibition of unjust economic discrimination. This assurance requires airports to provide to users equal access to airport facilities. Likewise, tenant businesses (e.g. FBOs) operating at airports are required to make services available and price those services not in an unduly discriminatory fashion. Although FAA is required to ensure that airports, as a condition for accepting federal grants, provide fair and equal access to services and nondiscriminatory pricing, FAA does not regulate prices in the FBO industry. As a condition of accepting federal grants, airports have a responsibility to ensure that they and their contractors and concessionaires abide by the grant assurances. FAA’s Airport Compliance Office oversees airports’ adherence to grant assurances by taking and responding to inquiries and complaints, developing and circulating advisories and guidance documents, and coordinating with airports and industry to conduct compliance training and airport land use inspections. The Department of Justice (DOJ) also plays a role in overseeing the FBO industry under its antitrust responsibilities to preserve competition. For example, in the Final Judgement entered by a federal court in the DOJ’s case regarding the acquisition by BBA Aviation (Signature Flight Support) acquisition of Landmark Aviation, BBA was required to divest FBO facilities in six locations where the transaction would have created a monopoly or duopoly for FBO services. In addition, the court order required BBA to provide advance notice of certain future acquisitions for the 10-year duration of the final judgment. Based on our review of FBO and third party websites, we found that fuel prices at FBOs are readily available to anyone on the internet. Nearly all of the pilots we spoke with told us they use these resources for making flight plans. For example, current prices for fuel are readily available on third party websites such as AirNav and Sky Vector, among others, and on about a third of the websites for FBOs we visited. See figure 2 for a representation of a website providing FBO information. However, fees for other services such as for parking and aircraft handling are less transparent. Our review of FBO and third-party websites found that such fees are not always available online, and that fees may vary by type of aircraft, are sometimes waived, and are called by different terms. According to FBO staff we spoke with, fees for services other than fueling can be lengthy and unwieldy to post on their websites for multiple reasons. First, some fees will vary based on the size and approved weight of the aircraft. For example, the price sheet for services other than fuel at one FBO showed fees varying by the aircraft’s approved weight, so there were 11 different prices for each of those services. The same pricing sheet also included prices for dozens of incidental services, such as aircraft towing and lavatory service that are not based on aircraft weight. Additionally, customers may be eligible for discounts on fuel purchases either by volume or through a membership program. FBOs may also waive fees in some cases—for example, with a qualifying fuel purchase an FBO might waive a parking, ramp, or handling fee. Further, a few stakeholders and pilots we spoke to indicated that FBOs don’t always use the same terms for a fee. For example, a landing fee or a ramp fee might be a fee for doing essentially the same thing. Consequently, to find out how much an FBO visit will cost, 16 of the 18 pilots we interviewed told us they call the FBO in advance. Based on information such as their type of aircraft, length of stay, and other services they might require, the FBO provides an estimate of their total cost. Recently, some industry stakeholders have called for increased price transparency and consistency among FBOs regarding how they characterize their fees, and have taken some actions to increase the transparency of fees. A campaign called, “Know Before You Go,” developed through the cooperation of six aviation associations, encourages FBOs to communicate and expeditiously provide available services and a listing of currently applicable posted fuel prices, as well as fees and charges for other available services. Further, the campaign suggests that these fees and charges should be made accessible to aircraft operators online in a user friendly manner and with sufficient clarity. Additionally, it encourages customers to contact the FBO to ask questions so pilots can make informed decisions. In response, one large- chain FBO began posting fees online for piston aircraft at its locations and another FBO company created a trip calculator on its web site for pilots to calculate the cost of their visit (see fig 3). We also found that a third party company recently began a web site that provides FBO parking ramp fees similar to those providing fuel prices. In addition, AOPA invited FBOs to include their fees in the association’s online airport directory. The association also indicated it categorizes the variety of fees into basic types of fees such as landing, using a hanger, or using lavatory service to help clarify what pilots could be expected to pay. In October 2019, AOPA officials indicated that FBOs’ posting of fees had not increased as much as they hoped. Selected stakeholders we interviewed—including officials from 26 airports, 16 FBOs, as well as 18 general aviation pilots—highlighted key factors that may influence FBO prices at airports across the country. Our statistical model confirmed a correlation between certain key factors identified by stakeholders and FBO prices. Consistent with general economic theory, these factors fall into three groups: (1) an FBO’s costs, (2) demand for an FBO’s services, and (3) competition among FBOs. Selected stakeholders we interviewed highlighted cost factors such as airport leases, infrastructure investment, fuel, labor, and security as influencing FBO prices. They cited the following examples: Airport Leases. Airport leases dictate terms and conditions of contracts between an FBO and an airport and include provisions related to the services an FBO must provide for pilots. Depending on the specific requirements or minimum standards developed at a given airport, FBO lease requirements vary and can affect an FBO’s costs. For example, at one airport we visited, the FBO is required to offer an after-hours self-service fueling option, which necessitates the acquisition and maintenance of additional equipment. In another case, the manager at an FBO we spoke to said that its overhead costs are relatively high because it is required to offer flight training and aircraft maintenance as part of its lease. To offer these services the FBO needs additional hangar space and must pay qualified skilled employees. Infrastructure Investment. As with leasing costs, the greater the investment an FBO makes at an airport, the higher its prices to users may be. According to airport and interest group officials we spoke with, FBOs typically have 20 to 30 year leases during which they may make infrastructure investments such as building hangars or lounges, based on FBO’s assessment of customer demand for its services. For example, according to airport and FBO officials we spoke to, an FBO will choose to invest in high-end facilities and amenities if it determines there is sufficient demand and revenues earned are expected to be sufficient to recoup the costs over the term of the lease. Fuel Transportation Costs. FBOs generally sell two types of aviation fuel for general aviation aircraft: Jet A and 100 low lead (100LL). Jet A is generally delivered over long distances via pipeline. According to one petroleum company, 100LL is generally moved by truck, rail, or barge—less cost-effective methods of transport than pipeline—due to the smaller volumes being produced. Further, there are parts of the United States, specifically on the East Coast, where little or no 100LL is produced and, as a result, transportation costs can significantly affect the cost of fuel to the FBO. Labor costs. FBOs compete in the local labor market for staff. The cost of labor for FBOs may vary across local labor markets around the country. Further, a particular FBO may need specialized skills to provide the services they offer, and this factor can affect the FBO’s costs. For example, some FBOs offer maintenance services, so will have trained mechanics on staff to perform such services. State taxes. Aviation fuel excise taxes on 100LL vary considerably from state to state and may also affect the costs to a consumer. For example, both Oregon and Idaho have a lower state aviation fuel tax compared to neighboring Washington State. An FBO manager told us that in some cases, a pilot will fly over to Idaho to obtain less expensive fuel, even though he or she may base the aircraft in Washington. Security. Some airports—particularly those with commercial service—are responsible for implementing security requirements in accordance with their Transportation Security Administration (TSA)- approved security programs, notably the security of perimeters and access controls protecting restricted areas of the airport, such as ramps and taxiways. We found that some FBOs are responsible for security and access controls on their leased property based on our review of individual lease requirements and the airport security plan. These FBOs might require staff on site 24 hours a day to maintain airfield and perimeter security, a requirement that can increase FBO costs. For example, an FBO operating at an airport with commercial service told us that it is responsible for perimeter security on the land it leases from the airport. In addition, it is subject to unannounced security checks by TSA. In contrast, smaller general aviation airports without commercial service are not required to have as many security requirements. Selected stakeholders told us that the location of an airport may influence demand for FBO services. Economic theory indicates that increased demand for a service will generally result in increased prices, all else equal. In particular, stakeholders cited the following examples of demand factors that may influence prices: Busy and congested airports may have higher prices for FBO services due to greater demand. Prices may be higher during part of the year in locations with significant seasonal traffic, such as beach resorts with a summer high season and ski resorts with a winter high season. The increased demand at FBOs during high seasons results in higher prices than during the off season. An airport’s proximity to the central business district may be associated with higher demand and higher prices in such locations. In addition to cost and demand factors, the extent to which the market for FBO services is competitive may also influence prices. According to the stakeholders we interviewed, competition among FBOs may lead to lower prices than would be the case when only one FBO provides the service at that airport. In our analysis of FAA airport and FBO data, however, we found that nearly 90 percent of NPIAS airports that offer FBO services are served by only one FBO (see table 1). According to a Transportation Research Board report, a strong indicator of the number of FBOs that can be financially viable at an airport can be the amount of fuel sales. For example, two airport managers we spoke to said that there was an insufficient volume of fuel sold at their airports to support more than one FBO. While the majority of NPIAS airports in the contiguous United States have only one FBO, pilots we spoke to said that competition from FBOs at nearby airports can also affect prices. For example, within 30 miles of Spokane International Airport, there are five other airports, each of which is served by an FBO that may compete with the services provided at Spokane International. (See fig. 4) We asked selected managers of FBOs and airports and selected general aviation pilots to describe how off-airport competition may influence FBO pricing. FBO and airport managers told us that they view nearby airports as competitors and monitor the FBO prices at these locations. For example, an FBO manager in Maine told us he regularly checks the prices at the larger international airport that is nearby. This finding suggests that when an FBO sets its prices, it takes into account the extent to which nearby airports may compete for its services. On the buyer’s side of the market, 11 of the 18 general aviation pilots we interviewed told us that they generally “price shop” for aviation fuel. Further, most general aviation pilots we spoke with told us they use online flight-planning tools to map their route and consider the fuel cost and service fees of the airports along that route. Further, four pilots and an FBO manager indicated that on longer trips that require refueling before reaching a destination, pilots may have options that are hundreds of miles from each other. For example, when flying from California to Texas, a pilot could choose to stop either in New Mexico or Arizona to obtain fuel. In this scenario, a pilot would compare prices of many FBOs in those two states and likely choose one with lower fuel prices. Likewise, an FBO manager in Kansas indicated that for these types of customers, he competes with FBOs at airports more than 100 miles away. However, we interviewed some pilots who said that they do not consider every nearby airport as a substitute. To be a true substitute the airport must meet the pilot’s needs to be a viable option. For example, the airport’s runway must be of sufficient length for the aircraft, and some runways may be too short for certain aircraft. Also, pilots take into account the type of fuel offered at an FBO. The pilot of a piston-driven aircraft will be unable to refuel at an FBO that offers only jet fuel. Finally, some pilots said the price differential would need to be sufficiently large to compensate them for any inconvenience. Some mentioned that the price of 100LL would have to be 30 to 40 cents per gallon lower to affect their flight plan, while others put that threshold at a lower point, 25 to 30 cents per gallon. Pilots also told us they take travel time into account. For example, some pilots said that they would consider landing at an alternative airport with lower prices if it were no more than 20 to 30 miles out of their way and if the change in destination were to add no more than 10 to 20 minutes to their trip. As a first step in examining the relationship of FBO competition with pricing, we examined differences in the average posted prices for 100LL and Jet A across NPIAS airports in the contiguous United States where only one FBO sold a fuel type compared to airports at which more than one FBO sold that fuel, without controlling for other factors that might also be correlated with prices. We also calculated the average prices at airports with one FBO and airports with multiple FBOs for a subset of airports with an air traffic control tower. We examined this subset of towered-airports, as they generally have more operations, and thus more demand. As shown in table 2 below, the average price per gallon of aviation fuel was lower at airports with only one FBO than at airports with on-airport competition. For example, at airports with only one FBO, the average price posted for full-service 100LL was $5.01 per gallon, while the average price posted at airports with more than one FBO was about 73 cents higher. However, examining average differences in price fails to control for other factors that might be correlated with prices. In particular, airports that have more than one FBO are likely to be those that have higher traffic volumes and that are located in areas with larger populations and higher per-capita incomes—all factors likely correlated with higher prices. Therefore, to more fully assess the issue, we developed a statistical model that examines how fuel prices may be correlated with measures of competition when controlling for other factors, such as demand, that also may be correlated with prices. Our statistical model confirmed a correlation between selected cost and demand factors and FBO-posted pricing of full-service 100LL and Jet A. It also confirmed a correlation between some of the competition factors described by stakeholders and the price of aviation fuel. Our analysis included information on posted prices for both 100LL as well as Jet A. In addition to running the model for NPIAS airports in the contiguous United States for which posted prices were available (all-airports), we also ran the model for a subset of these airports that have air traffic control towers (towered-airports). See appendix II for a more detailed discussion of the model structure and findings. As we have noted, we expected fuel prices to be correlated with a variety of cost, demand, and competition factors that pertain to characteristics of airports and their locations, as well as characteristics of FBOs operating at airports. We found the following correlations: Airport Characteristics. Our model found that the size of an airport—measured as the total number of operations—was associated with higher prices for both 100LL and Jet A. The operational size of an airport is likely associated with higher demand for airport services and also is likely related to higher costs of providing those services. Specifically, we found that an increase of 10,000 airport operations per year was associated with higher prices of about 2 cents per gallon for both 100LL and Jet A in both the all-airports and towered-airports datasets. The length of the longest runway available at an airport was also correlated with higher fuel prices. The length of the runway is an indicator of the types of aircraft an airport can support. In particular, longer runways are able to accommodate larger and heavier aircraft— aircraft that generally use more fuel and thus may indicate higher demand for fuel at the airport. Specifically, we found that a 1,000-foot increase in runway length was associated with a higher price of about 7 to 8 cents per gallon for both fuels. Demographic Characteristics of Airport Location. Our analysis found that FBOs’ fuel prices were generally higher at airports in areas with higher incomes, but not always at airports in areas with larger population. We found that prices for both types of fuel were higher at airports located in counties with higher per-capita incomes. Where incomes are higher, we would expect the demand for travel to be greater. Moreover, where there are higher incomes, the cost of providing FBO services—particularly labor costs—are likely higher. We found income correlated with fuel prices for both the 100LL and Jet A in the all-airports datasets and for 100LL in the towered-only airport dataset. We also found that 100LL aviation fuel prices were higher at airports located in counties with larger populations. This was expected due to the likely greater demand for air travel in more populous areas. However, county population was not statistically significant in relation to the price of Jet A. Geographic Characteristics of Airport. Our model found that airports located in states on the East Coast tend to have higher 100LL prices. Specifically, the model suggests that 100LL prices are between 22 to 26 cents higher per gallon on average in these states. We expected FBOs operating in East Coast states to have higher 100LL prices due to higher transportation costs, as we found that there is no production of 100LL in these states. As mentioned earlier, 100LL is generally moved by truck, rail or barge due to the smaller volumes being produced—a less cost-effective means of transport than pipeline. Jet A, on the other hand, is transported by pipeline over long distances. We thus expected higher prices for 100LL at airports in these states. We found this geographic differential in all specifications for the 100LL model. Large-Chain FBOs. Our model found that both types of fuel tend to have higher posted prices at airports that have a large-chain FBO operating on the premises, regardless of whether or not there was another competitor on the premises. Specifically we found that when a large-chain FBO operates at an airport, fuel at the airport tends to be more expensive on average—on the order of 60 cents more per gallon for 100LL, and an even greater differential for Jet A, more than $1.20 per gallon. Availability of Self-Serve 100LL fuel. Our model found that when self-serve 100LL is available at an airport, the prices for full-serve 100LL tend to be lower than at airports with no self-serve 100LL available. Specifically, we found that if a self-serve 100LL option is available at an airport, the price of full-service 100LL will be about 10.5 cents per gallon lower, on average, compared to FBOs at airports without self-service 100LL. We expected a self-service option might be correlated with somewhat lower prices for full service 100LL—even if the full service option is provided by the same FBO— because pilots are presented with a lower price option may constrain the prices that FBOs will charge for a full-service option. Competition. Within our statistical model, we examined whether the extent of competition among FBOs had a correlation with fuel pricing in two ways. On-airport competition. On-airport competition occurs when two or more FBOs at an airport sell the same kind of fuel. We estimated that the price of Jet A is lower, on average, at an airport when two or more FBOs provided that fuel at an airport. Specifically, for the all-airports dataset, we found that, on average, the posted price of Jet A was 35 cents per gallon higher if only one FBO sold the fuel at an airport compared to the case when at least one additional competitor also served the airport. In the towered-airports dataset, the posted price of Jet A was about 50 cents higher on average if there were only one FBO at the airport. For 100LL, we did not find a statistical relationship between on- airport competition and prices in the all-airports dataset; however, we did find a statistical relationship between on-airport competition and prices in the towered-airports dataset. The finding of no correlation between on-airport competition and 100LL prices may be linked to the rarity of airports with more than one FBO selling 100LL in the all-airports dataset. In fact, in the all-airports dataset, only 13 percent of FBOs faced on-airport competition in the sale of 100LL while in the towered-airports dataset about one-third of FBOs faced competition in the sale of 100LL. Specifically, we estimated that the price of 100LL is 11 cents lower, on average, if there are at least two FBOs selling that fuel at a towered airport. Nearby competition. Our model also tested whether the availability of additional FBOs at airports within a 30-mile distance from a given airport had any correlation to prices for 100LL. We included this factor because many of the stakeholders we spoke to noted that general aviation pilots will consider using an airport near their preferred airport if prices were more favorable at the alternative location. However, across all model specifications, we did not find that prices for 100LL were correlated with the presence of FBOs at nearby airports. FAA officials told us they primarily rely on airports to self-certify their compliance with federal airport grant assurances when they accept AIP grant funding. This reliance includes the grant assurance that relates to FBO fees—an airport must ensure aeronautical services are available to all users on a reasonable and not unjustly discriminatory basis. FAA officials indicated that airport compliance staff conduct outreach to stakeholders and provide training aimed at ensuring that airports comply with these assurances. One recent outreach effort focused on FBO pricing. Additionally, FAA responds to phone and email inquiries and informal and formal complaints, and conducts periodic airport land use inspections, as discussed below, but none of these efforts has identified FBO pricing as a widespread area of concern. Training and Outreach. According to FAA, compliance staff conducts periodic training and outreach to the airport community on a variety of compliance issues. FAA headquarters annually conducts recurrent compliance training—which includes overseeing airport grant assurances—with regional and other FAA offices. FAA officials told us they use these sessions to address concerns brought up by regional compliance officials and airport compliance staff. One example of FAA’s outreach efforts occurred in December 2017 after AOPA raised questions about FBO pricing earlier that year. To bring clarity to the issue of FBO pricing and the role of FAA, the agency released questions and answers that emphasized: (1) FAA does not regulate FBO prices; and (2) airports are responsible for ensuring FBO prices are reasonable and applied in a non-unjustly discriminatory manner. Furthermore, FAA stated that whether an FBO’s fees are reasonable (i.e., higher than average than other FBOs) involves a number of economic, business, and other factors that vary widely from airport to airport and FBO to FBO and may include underlying costs, market conditions, quality of service, and other factors. Inquiries and Complaints. According to FAA, airport compliance staff respond to (1) phone and e-mail inquiries, (2) informal complaints, and (3) formal complaints. FAA officials told us that, while FAA does not regulate FBO prices, if someone contacts them with inquiries or a concern about a potential grant assurance violation, such as one involving FBO prices, they first refer the issue to the local airport to resolve. If the issue is not resolved, the complainant may file an informal complaint with an FAA regional office. According to FAA guidance, each FAA regional office will review the complaint and issue a letter indicating whether FAA sees a grant violation that the airport should fix or not. If the complainant is dissatisfied with the regional office’s letter, the complainant may then file a formal complaint about a violation of grant assurances with headquarters. Headquarters will then review the circumstances of the complaint and make a formal determination as to whether a grant violation occurred and work with the airport to address the violation. Data on informal and formal complaints filed with FAA headquarters and regional offices indicate FAA has not received many complaints on FBO pricing. Specifically, we reviewed informal complaint data from 2013 through 2018 from each FAA region, and found a total of 142 informal complaints about potential grant violations. Seven of these complaints related to FBO prices, and FAA found one violation later resolved by the airport by providing space for aircraft to do routine maintenance. In addition, we obtained and reviewed FAA’s responses to formal complaints from 2013 through 2018, and found that none of these formal complaint responses dealt with FBO prices. While FAA received few complaints related to FBO prices, there are limitations in relying on complaint data to understand the magnitude of an issue. For example, some pilots we spoke with stated if they have an issue with an FBO, they will use an alternative FBO rather than submit a complaint to FAA. We found that in addition to informal and formal complaints, each FAA regional office independently records inquiries about airport grant assurance issues ranging from inappropriate hanger use to noise complaints to FBO lease arrangements. Further, each region varies in the way it captures airport compliance information such as airport location, dates, and description of an inquiry or concern. For example, some regions indicate the specific grant assurance that was potentially violated while others simply describe the nature of the concern. To help see if there is a pattern of concerns across the country, FAA’s Office of Airport Compliance in headquarters has an initiative to centralize information on inquiries and concerns about grant assurances, including any that may be related to FBO prices. As envisioned, this “Enhanced Information Sharing Initiative” will provide FAA compliance staff with the ability to record and track inquires and complaints in comparable systems and should facilitate information sharing among regions and between regions and headquarters. According to FAA officials, centralizing this information will help identify issues that may be of a concern to airport users. According to FAA officials, this initiative, originally planned to be completed in August 2019, has faced delays due to a government shutdown earlier this year and information technology security difficulties. However, FAA has hired a new contractor and anticipates completion sometime in fiscal year 2020. According to an FAA compliance manager, problems that arise in the regions are brought to the attention of the airport compliance offices and discussed, and whether additional actions should be taken. Airport Land-Use Inspections. FAA is required to conduct a minimum of two airport land-use inspections per year per region, reviewing whether airports are complying with grant assurances such as airport property use requirements and lease agreements. We reviewed FAA’s annual land use inspection reports to Congress from fiscal year 2013 through 2018 and did not identify any FBO pricing concerns. We provided a draft of this report to DOJ and DOT for review and comment. DOJ provided technical comments, which we incorporated as appropriate. DOJ also suggested that we discuss more directly the implications that airport ownership of FBOs might have for fuel prices. We agree that airport-owned FBOs might price fuel differently than privately- owned FBOs. However, we were not able to obtain reliable data on airport ownership of FBOs. DOT did not have any comments. We are sending copies of this report to the appropriate congressional committees, the Secretary of the Department of Transportation, the Attorney General, and other interested parties. In addition, the report is available at no charge on the GAO website at http://www.gao.gov If you or your staff any have questions about this report, please contact me at (202) 512-2834 or VonahA@gao.gov. Contact points for our Offices of Congressional Relations and Public Affairs may be found on the last page of this report. GAO staff who made key contributions to this report are listed in appendix III. This appendix describes a model we developed to assess factors that may correlate with fixed base operator (FBO) aviation fuel prices across airports. The model uses data on posted prices for full-service 100LL aviation fuel (100LL) and Jet A (Jet A) fuel at a sample of airports in the contiguous United States that are part of the National Plan of Integrated Airport Systems (NPIAS), along with data on selected other factors that may be correlated with fuel prices. Specifically, this appendix discusses (1) the structure of the model, data sources, and variable definitions, and (2) base-case and alternative model results. Based on our audit work as well as economic reasoning, we hypothesized that a variety of factors may be correlated with aviation fuel prices across airports. Generally, factors that influence the price of any product are the demand for the product, the cost of producing and marketing the product, and the extent of competition among those selling the product. To examine the correlation between these factors and the price of both 100LL and Jet A fuel sold by FBOs, we developed an econometric model. Specifically, our model analyzed the independent correlation of selected key factors with aviation fuel prices. We used several specifications of the model for both full-service 100LL and full-service Jet A. Each specification used airport-level data to analyze variation in the price of a single type of fuel across airports. For each type of fuel, we included only NPIAS airports within the contiguous United States for which our data on aviation fuel prices reported a price for at least one FBO. In addition, we ran the analysis not only on the full dataset of all of the airports for which we were able to obtain fuel-pricing information (which we refer to as the all-airports dataset), but also on a subset of airports limited to those with an air traffic control tower (towered-airports dataset). For each type of aviation fuel, the dependent variable—or the variable to be explained in the model—is the average price of that fuel at an airport, net of state taxes. If an airport has only one FBO selling a fuel, the average price of that fuel at that airport is simply the price charged by the FBO that sells it. At an airport where two or more FBOs compete to sell the same type of fuel, the average price of the fuel is calculated as a simple (unweighted) average across all of the FBOs that sell the fuel at the airport. For 100LL, about 87 percent of airports in the all-airports dataset are served by only one FBO, and for Jet A, the share is lower, at about 84 percent. We obtained data on posted aviation fuel prices from a company that publishes such data online for two separate dates—a Wednesday in October of 2018 and a Wednesday in May of 2019. All of the fuel price data we received had been updated within 30 days of these dates. Independent variables in our model included a variety of demand, cost, and competitive factors that we hypothesized may explain the variation in fuel prices across airports. In particular, these factors relate to characteristics of (1) airports, (2) the locations where an airport resides, (3) the FBOs operating at a given airport, and (4) the availability of competing FBOs. Characteristics of airports. We expected certain characteristics of each airport to be related to the level of fuel prices. Airport size. We measured airport size based on the number of total operations—takeoffs and landings—at the airport. Greater activity at an airport reflects higher demand for services, which we expected to correlate with higher prices. Moreover, it is likely more costly to provide services at these busier airports. As such, based on both demand and cost factors, we expected larger airports to have higher fuel prices. We obtained data on airport operations from the Federal Aviation Administration (FAA). Length of the longest runway. Longer runways can accommodate larger and heavier aircraft, which may increase demand of such traffic. Because larger and heavier aircraft require more fuel, a longer runway may be indicative of greater demand for fuel at the airport. At the same time, longer runways are more costly to construct and maintain. Thus both demand and supply factors related to having a longer runway would suggest that fuel prices could be higher at such airports. We obtained information on runway length, which we measure in thousands of feet, from FAA. Characteristics of locations. We also expected demographic and geographic characteristics of the location of each airport to be correlated with fuel prices. Demographic characteristics of the population living in the area near an airport. Personal income per capita. Areas where per-capita incomes are higher could signal a greater demand for air travel and airport services. At the same time, areas with higher per-capita incomes also suggest that costs for labor and other resources the FBO will need to procure will be higher. Thus, we hypothesize that airports located in counties with higher per-capita incomes will have higher fuel prices. We obtained data on personal income per capita by county from the Bureau of Economic Analysis, Department of Commerce. Square of per-capita income. We also expected that, as income levels rise, the effect of even higher levels of income on fuel prices will attenuate. To account for the possibility of a nonlinear relationship between income and fuel prices, we included a variable equal to the square of personal income per capita. Population. A larger population in the area surrounding an airport would likely indicate higher demand for airport services. We obtained population data by county from the Bureau of Economic Analysis, Department of Commerce. Distance from Source of 100LL aviation fuel production. Following production, 100LL is typically shipped over longer distances by truck, rail, or barge, while Jet A tends to be transported over longer distances by pipeline. As such, long-haul transport is relatively more costly for 100LL. We found that there is no production of 100LL in East Coast states, while most other states in the contiguous United States have production sources for 100LL in closer proximity. Therefore, we controlled for the greater cost of transporting 100LL to states along the East Coast with a dummy variable in the 100LL pricing model. We obtained information on production sources for 100LL from the Energy Information Administration, Department of Energy. Characteristics of FBOs. We included two variables in the model that relate to the services provided by FBOs at the airport Large-Chain FBOs. Based on our audit work, we hypothesized that large-chain FBOs—those with operations at numerous airports—are more likely to focus their business model on meeting the demands of pilots looking for a suite of services and amenities. We thus expected that an airport served by a large-chain FBO may have higher average fuel prices due to the costs of providing such services. We used the data on aviation fuel prices to determine the number of operations run by each FBO. For purposes of the model, we defined an FBO as a large-chain if the owner had at least 25 FBO operations across airports reported in our dataset. Availability of self-service fuel at airport. We hypothesized that the price for full-service 100LL might be lower at an airport where a self- service 100LL is also offered for sale. That is, the ready availability of a cheaper fueling option may influence the pricing of full-service 100LL. Therefore, we included a dummy variable in the 100LL pricing model if self-service 100LL was also available at the airport. In many cases, only one FBO is available at an airport and provides both self- service and full-service 100LL. The variable is derived from the data on aviation fuel prices. Degree of competition among FBOs. Economic theory suggests that market prices for a product will be lower when more firms are selling a product, all else equal. We examined “on-airport” competition among FBOs for both fuels, and for 100LL, we also developed a variable to account for competition at nearby airports. The number of on-airport FBOs selling a given fuel. The most immediate and likely relevant competition among FBOs would occur at a given airport. To examine the correlation between on-airport competition and aviation fuel prices, we used two alternative measures: (1) the number of FBOs selling the fuel at each airport and (2) a dummy variable that equals 1 for airports where more than one FBO sells the fuel and 0 otherwise. These competition measures were derived from the data on aviation fuel prices. Availability of alternative FBOs at airports in the vicinity. Because stakeholders we interviewed said that pilots using 100LL may consider using nearby airports where that fuel is less expensive rather than their intended destination airport, we examined whether the availability of FBO services at nearby airports correlated with 100LL prices. Specifically, we counted the number of different FBOs selling 100LL at airports within a 30-mile radius of each airport where 100LL is sold. We derived this measure of competition from nearby airports by combining geospatial data for each airport with information from our data on aviation fuel prices. As noted, we ran the fuel-pricing model for both 100LL and Jet A aviation fuels. Table 4 provides descriptive statistics for all of the variables included in the models. We report regression results for several specifications in tables 5–9. Specifically these tables provide the extent and direction (plus or minus) of the estimated correlation of each of the independent variables on aviation fuel prices. We also indicate whether each estimated correlation is statistically different from zero. The per-gallon price of aviation fuel (100LL and Jet A)—the dependent variable in our model—is measured in dollars and cents. Some of the independent variables are measured in levels—for example, annual airport operations are measured in tens of thousands, and the length of the longest runway in thousands of feet. For these variables, the regression model results indicate the estimated correlation of a one-unit increase in the level of the independent variable on the price of aviation fuel. For example, as shown in table 4, an increase in runway length of 1,000 feet is associated with an increase in the price of both 100LL and Jet A of about 8 cents, and this estimated correlation is statistically different from zero at the 1 percent level. The model also includes some “dummy” variables—variables that take a value of either 1 or 0, depending on whether a specific attribute does or does not apply. For a dummy variable, the estimated correlation is interpreted as the effect of the attribute on the per-gallon fuel price. Based on the findings in table 5, being located on the East Coast is associated with an increase in the price per gallon of 100LL fuel of about 22 cents. This correlation was also found to be statistically different from zero. In another example, the model specification shown on table 5 uses a dummy variable to indicate the presence of competition at an airport—the variable equals 1 for airports that are served by more than one FBO and 0 for airports that are served by only one FBO. Results in table 5 indicate that the price per gallon of Jet A fuel is about 35 cents lower at airports that are served by more than one FBO than at airports with only one FBO. In addition to the individual named above, Cathy Cowell (Assistant Director); Nick Nadarski (Analyst-in-Charge); Amy Abramowitz; Dave Hooper; Christopher Jones; Ned Malone; Malika Rice; Ardith Spence; and Michelle Weathers; made key contributions to this report.

Summary: Since 2007, the FAA has provided more than $37 billion in grants to airports to fund capital development and is responsible for ensuring compliance with requirements airports assume when they accept these grants. One such requirement is that the airports provide users equal access to airport services such as fueling and parking. Recently, an industry group and pilots raised concerns about the transparency and reasonableness of prices charged for these and other services at airports. GAO was asked to examine FBOs' pricing and FAA's oversight of related airport grant assurances. This report examines: (1) the transparency of FBO prices, (2) the factors that influence prices, and (3) the extent to which FAA ensures compliance with federal airport grant assurances related to FBO activities. GAO analyzed FAA data related to complaints from 2013 through 2018 and reviewed relevant literature, key laws and regulations, and program documentation. GAO developed a statistical model to analyze variation in fuel prices across airports in the contiguous United States. GAO interviewed FAA compliance staff at headquarters and all regional offices, as well as a non-probability selection of stakeholders. Fixed base operators (FBO) at airports (see figure) offer a variety of services to pilots and passengers. While anyone can view fuel prices offered by FBOs online, other service fees, such as for aircraft parking, can vary by type of aircraft and are not always available online, although they can be obtained by calling the FBO. Recently, industry groups developed the “Know Before You Go” campaign that calls for greater transparency of FBO prices. Some of the FBOs GAO interviewed list their fees online; however, others do not. Stakeholders GAO interviewed––including general aviation pilots, airports, FBOs, and industry groups––said FBOs' costs to build and maintain facilities—such as hangars and fueling facilities—as well as operating expenses such as labor and fuel––influence their prices. Stakeholders also said that demand for FBOs' services can influence prices, such as when seasonal demand affects operations at an airport near a ski resort. Finally, they also said that competition affects FBO's prices. GAO's statistical model confirmed a correlation between many cost and demand factors and aviation fuel prices and found higher prices at airports with higher costs and demand. This model also found that on-airport competition is associated with lower prices at the country's busiest airports: Prices for aviation fuels were lower at such airports with more than one FBO. However, not all airports can support more than one FBO due to, for example, the amount of business each gets. Airports receiving Federal Aviation Administration (FAA) grants must meet “grant assurances” such as charging reasonable and not unjustly discriminatory prices for services, including prices charged by FBOs. FAA officials said FAA oversight relies on (1) airports' consent to adhere to grant assurances; (2) training and outreach; and (3) complaints. Since 2013, in complaints received by FAA, GAO found few complaints about FBOs' prices. GAO found each regional office independently records additional inquiries. FAA is moving to collect regional inquires centrally, and by 2020 that step may allow FAA to stay abreast of apparent nationwide trends or issues with any grant assurance concerns.