What Ancillary Revenue Includes
Airline ancillary revenue encompasses all income generated from sources beyond the base passenger fare. According to the IdeaWorksCompany 2025 Yearbook (covering 61 airlines), the category includes a la carte services paid directly by passengers (baggage fees, seat selection, onboard food and Wi-Fi), commissions earned from third-party travel products (hotel bookings, car rentals, travel insurance), and revenue from the sale of frequent flyer miles to co-branded credit card partners — which represented 40–50% of ancillary revenue for Delta, American, and United in 2024.[1][2][4]
IdeaWorksCompany and CarTrawler projected global airline ancillary revenue at $148.4 billion for 2024. For 2025, IdeaWorksCompany projected $157 billion in global ancillary revenue.[2][3]
Ancillary revenue contributed 14.9% of total airline revenue globally in 2024, up from 9.1% in 2016. IdeaWorksCompany projects that share at 15.7% for 2025.[3][4][1][2]
The Largest Ancillary Revenue Generators
The IdeaWorksCompany 2025 Yearbook of Ancillary Revenue, covering 61 airlines' 2024 financial disclosures, ranks the top three carriers by total ancillary revenue as United Airlines ($10.6 billion, 18.6% of total revenue), Delta Air Lines ($10.2 billion, 16.8%), and American Airlines ($9.2 billion, 17%).[4][1]
Among carriers where ancillary revenue exceeds half of total revenue, five airlines crossed the 50% threshold in 2024:[1]
| Airline | Ancillary as % of Total Revenue (2024) | Type |
|---|---|---|
| Frontier Airlines | 62% | ULCC |
| Spirit Airlines | 58.7% | ULCC |
| Breeze Airways | 54% | LCC |
| Allegiant Air | 52.9% | ULCC |
| Volaris (Mexico) | 51.7% | ULCC |
On a per-passenger basis, the highest ancillary revenue in 2024 among the 61 airlines in the IdeaWorksCompany 2025 Yearbook was reported by Norse Atlantic Airways ($100.40), Jet2.com ($89.99), and Breeze Airways ($89.82).[5][4]
Baggage Fees
U.S. airline baggage fees date to May 5, 2008, when American Airlines introduced a $25 first-bag charge. By 2023, BTS reported $7.0 billion in baggage fee revenue for 18 U.S. carriers.[6][1]
BTS data for Q3 2025 shows baggage fees at $2.0 billion, representing 3.1% of total operating revenue for all 23 scheduled U.S. passenger airlines — up from 3.0% in Q3 2024.[7]
Southwest Airlines ended its decades-long free checked bags policy in mid-2025, marking the end of the last major U.S. carrier holdout on baggage fees. BTS data for Q3 2025 reflects the first full quarter under the new fee structure.[6]
Seat Selection: Overtaking Baggage at United Airlines
For carriers that report seat selection revenue separately, this category has grown to rival baggage fees. At United Airlines, seat selection revenue surpassed baggage fees in 2024 — the first time seat selection exceeded baggage at a major U.S. carrier (United 2024 10-K).[1]
Loyalty Programs and Co-Branded Credit Cards
For U.S. network carriers, the sale of frequent flyer miles to co-branded credit card issuers represents the single largest component of ancillary revenue. In 2023, Delta Air Lines received $6.8 billion from American Express, American Airlines reported $5.2 billion from co-branded card and partnership revenues, and United Airlines reported $3.2 billion primarily from payments to its MileagePlus program.[8]