Most of our revenues are driven by the operations of a few key airline customers. In 2023, Concesionaria Vuela Compañía de Aviación, S.A. de C.V. ("Volaris"), Aeroenlaces Nacionales, S.A. de C.V. ("VivaAerobus"), Grupo Aeroméxico, S.A.B. de C.V. ("Aeromexico" a holding company that owns Aeroméxico and Aeroméxico Connect) and American Airlines, Inc. ("American Airlines") transported a significant percentage of our passenger traffic. During 2023, the passenger charges collected by these four airlines accounted for 16.6%, 6.1%, 5.1% and 4.0%, respectively, of total revenues at our airports (21.6%, 7.9%, 6.7% and 5.2%, respectively, of the sum of aeronautical and non-aeronautical revenues generated at our airports in 2023).
The global airline industry has recently experienced and may continue to experience significant difficulties, marked by the filing for bankruptcy protection of several carriers. For instance, in June 2020, Aeromexico announced that it had filed for Chapter 11 bankruptcy due to the unprecedented challenges related to the COVID-19 pandemic. After 20 months, in March 2022, Aeromexico successfully completed its financial reorganization process. During 2021, 2022 and 2023, the passenger charges collected by Aeromexico accounted for 5.0%, 5.3%, and 4.0% of total revenues in our airports, respectively (6.0%, 6.4%, and 5.2% of the sum of aeronautical and non-aeronautical revenues generated in our airports in 2021, 2022, and 2023, respectively).
If any airline customer that seeks to restructure or recapitalize is unable to do so successfully or if our commercial arrangements with these key airline customers are not maintained, any investments or other assets associated with those airline customers could become impaired, and our business and results of operations could be materially adversely affected.
None of our contracts with our airline customers obligate them to continue providing service to our airports, and we can offer no assurance that if any of our key customers reduce their use of our airports, competing airlines would add flights to their schedules to replace any flights no longer handled by our principal airline customers. In addition, Mexican law prohibits an international airline from transporting passengers from one Mexican location to another. This is except if the passenger originated travel outside Mexico, thus limiting the number of airlines providing domestic service in Mexico. Accordingly, we expect to continue to generate a significant portion of our revenues from domestic travel from a limited number of airlines.
Furthermore, passenger charges, which accounted for 52.5%, 52.8%, and 48.3% of our revenues in 2021, 2022, and 2023, respectively (63.8%, 64.1%, and 63.2%, respectively, when taking into account only the sum of aeronautical and non-aeronautical revenues), are collected, pursuant to passenger charges collection agreements, by airlines from passengers on our behalf and are later paid to us, depending on the airline, within no more than 60 days following the date of each flight. During 2021, 2022, and 2023, the average collection term for passenger charges was 62, 63, and 62 days, respectively. See "Item 4, Information on the Company – Business Overview – Our Sources of Revenue – Aeronautical Services – Passenger Charges – Passenger Charges in Mexico." Consequently, if any of our key airline customers were to become insolvent or seek bankruptcy protection, we would be an unsecured creditor with respect to any unpaid passenger charges, and we would not be assured of collecting the amounts invoiced to that airline for passenger charges despite cash deposits held in guarantee. Additionally, we could not be assured that we would recover the traffic they had stopped transporting. Both scenarios could negatively affect our cash flows from operations or our results of operations.
Additionally, if some of our commercial clients were to face difficulties making their payments to our airports, some clients may decide to leave our commercial spaces and cancel their contracts. This could potentially have a negative effect on our revenues.