Kate Hanni of California and Catherine Ray of Arkansas allege false imprisonment, fraud and negligence.
Their flights about a year ago were diverted from Dallas/Fort Worth Airport to Austin on Dec. 29, 2006 because of stormy weather, The Fort Worth (Texas) Star-Telegram reported Tuesday.
After landing in Austin, passengers remained in the planes for hours and weren't allowed to get off despite overflowing toilets and little food or water.
The two women have filed suit seeking class-action status. They claim that American Airlines' decisions that day negatively affected about 12,000 passengers.
Hanni has lobbied Congress to pass an "airline passenger's bill of rights" that would guarantee minimum service levels for air travelers.
American officials said they haven't seen the lawsuits and could not comment, but company spokesman John Hotard told the newspaper the airline has taken steps to improve its system for dealing with severe weather.
In 1999, a class-action suit against Northwest Airlines covered more than 7,000 passengers who were stuck for up to 11 hours during a snowstorm in Detroit. The airline eventually settled out of court for $7 million.