Rio Yamat | Associated Press

The collapse of Spirit Airlines isn't the only curveball confronting people planning summer trips. Rising jet fuel costs tied to the Iran war have pushed up airfares and associated fees across the industry. Two of the remaining U.S. budget carriers just finalized a merger. The developments illustrate how difficult it's gotten for low-cost airlines to operate while squeezed by jet fuel prices, changing consumer preferences and competition.

Spirit Airlines says it plans to furlough 1,800 flight attendants before the end of the year. starting Dec. 1 to match staffing with expected flight demand during its second bankruptcy in a year. The cash-strapped budget carrier said Monday that it made the “difficult decision” to put cabin crew members on temporary leave to match staffing needs with expected flight demand during Spirit’s second bankruptcy filing in a year.