Today, four big carriers account for more than two-thirds of the U.S. domestic passenger airline industry: Delta, Southwest, American, and United. Delta, the largest, is also the least-unionized.
Most heavily unionized is American Airlines, which also tends to bargain new contracts relatively quickly. Under federal law, union contracts don’t expire at airlines, but have a date after which they can be amended. At the end of 2024, just 7% of union-represented employees at American had contracts that had passed their initial term length.
Southwest is all good with its unions too at the moment. Last September, t completed a two-year process to negotiate new contracts with its 12 unions in September 2024, so none of its unionized employees are working under old contracts.
But at United, more than 60% of union workers are working under old contracts, and around 28,000 flight attendants represented by the Association of Flight Attendants (AFA) haven’t gotten raises since 2020. United flight attendants authorized a strike in 2024 and reached a tentative agreement with AFA in May 2025, but members rejected the agreement in July.
Alaska Airlines — the biggest airline at the Portland and Seattle airports — is 84% union in its core, but its subsidiary Horizon Air is only 42% union. Alaska purchased Hawaiian Airlines (82% unionized) last year and plans to negotiate contracts that cover similar workers at both airlines, who are represented by the same unions. Alaska flight attendants rejected a tentative agreement in 2024 but accepted a new contract in February 2025, earning immediate pay raises up to 28%.
With just over half of its workers unionized, JetBlue has the second lowest union rate of the major airlines. IAM and Transport Workers Union (TWU) both ran JetBlue union organizing campaigns in 2024 that have since gone silent.
