Removing the grounded Boeing 737 MAX from their flight schedules was painful enough for the three U.S. airlines that flew the aircraft. Losing the jets during the lucrative spring break travel season makes it even worse.

Trimmed flight schedules, which has already begin to disrupt plans for some of the 157 million college students and others the industry expects to fly U.S. carriers from late February through the end of April, will erode the accompanying seasonal sales boost for American, Southwest, and United airlines.