For arrivals beginning in 2021, Walt Disney Travel Company will no longer offer air transportation as part of its packages for Guests traveling to Walt Disney World® Resort, Disneyland® Resort and Aulani, a Disney Resort & Spa.
This includes both consumer-direct and third-party bookings.
Disney will continue to make new airline bookings for travel through the end of 2020, and will continue to service existing airline bookings at this time.
Source: Disney Destinations