Frontier's first attempt to merge with Spirit was in 2022, but it was outbid by JetBlue.
Frontier is optimistic that it can get a deal done this time around.
The announcement comes less than two weeks after the Transportation Department fined JetBlue $2 million for chronic delays.
The government says it's the first such fine against an airline over chronic delays, and it blames JetBlue for 'unrealistic scheduling.'
The two weekends on either side of Christmas are tempting a lot of people to head out earlier.
The last bankruptcy by a major U.S. carrier was when American Airlines simultaneously merged with US Airways in December 2013.
The Justice Department could still challenge the Alaska-Hawaiian deal, but that appears unlikely.
The department will take comments on the proposed family seating rule for the next 60 days before it crafts a final rule.
Southwest made the announcement on the same day that both it and American Airlines reported a steep drop in second-quarter profit.
The Reno-Tahoe International Airport will be expanding its nonstop flight options later this year.