The lawsuit states that at every instance, the airlines were told and reminded of Vilma's condition by both the travel agent and the couple. It states that the defendants acted in "willful, wanton and reckless disregard" for Vilma Soltesz.
"We believe the suit is entirely without merit. After the operating carrier in Budapest was physically unable to board Mrs. Soltesz on its flight, and despite a determined good-faith effort by Delta in Prague, we were also physically unable to board her on our aircraft on Oct. 16.," Delta said in a statement.
"Delta employees did everything possible to assist the Soltesz family with their travel, but unfortunately Mrs. Soltesz' physical condition was such that she was unable to be boarded on the aircraft."
KLM and Lufthansa did not return ABC News' request for comment.