How to file a complaint with the airlines
You can file a complaint with the airline directly, but make sure to file with the DOT as well.

How to file a complaint with the Department of Transportation
You may file a complaint with the Department of Transportation’s Aviation Consumer Protection Division on their website . For airline service complaints, you may also call the ACPD at 202-366-2220 (TTY: 202-366-0511)

How to contact
You are encouraged to send us a copy of their complaints. Flyers Rights operates a Toll Free Hotline at 1-877-FLYERS-6. Our hotline provides consumer information, but we do not engage in legal representation.

In-flight Complaints and Disagreements
While on the aircraft, passengers are required to follow the instructions of the flight crew, even if those instructions seem unfair or even unlawful. The captain and flight crew are responsible for the security and safety of everyone on board the aircraft. Complaints should ordinarily be made after the flight has ended. In emergency circumstances, the passenger may ask the flight attendant to convey their request to the captain, who has the final authority during the flight. Passengers should document the situation as much as possible for potential later use. Under the Patriot Act, flight crew are empowered to charge passengers with the crime of interfering with flight operations.