Pinnacle Airlines will be relying primarily on 50-seat regional jets to carry it out of bankruptcy and until at least July 2022, when its newly revised contract to operate them for Delta Air Lines expires, even though the 50-seater market is shrinking and has a long-term future that is suspect at best.

That might not be the best foundation on which to build a future, but it may be the best option for the nearer-term survival of Pinnacle, the parent company for regional carriers Pinnacle Airlines, Colgan Air and Mesaba Airlines, or buy it time to transition to bigger aircraft. Memphis, Tenn.-based Pinnacle says in its bankruptcy court filings that its CRJ-200 contract with Delta is one of only two capacity purchase agreements at the regional carrier that are “potentially viable.”

The other is a contract to fly 41 CRJ-900s for Delta—all of which are under Delta lease—that also lasts until July 2022. For Delta, those aircraft are used in a two-class configuration with 76 seats, but can carry 90 passengers in an all-coach configuration.

As part of the restructuring, Pinnacle and Delta reached an agreement on early termination of a separate contract to operate 16 Pinnacle-owned CRJ-900 aircraft for Delta, which will wind down that flying over a five-month period that begins in January 2013.

Pinnacle is not yet saying what it plans to do with those 16 aircraft as they come off the Delta contract, so it is not clear whether they will remain in its fleet. The regional airline, however, definitely is getting rid of all of its Bombardier Q400 and Saab aircraft.

That means, by mid-2013, it might only be flying those 140 50-seat CRJ-200 aircraft and anywhere from 41 to 57 of the CRJ-900s.

The number of CRJ-200s is likely to dwindle between now and 2022: Under the newly revised Delta-Pinnacle capacity purchase agreement on the CRJ-200s, Delta can remove CRJ-200 aircraft from Pinnacle’s fleet, effective on the expiration date of Delta’s financing arrangement for each aircraft.

Pinnacle will not disclose the timing or number. Delta also can reduce the number, on a one-to-one basis, if it reaches agreements with Pinnacle for flying more regional jets with 70 or more seats.

A profitable future for the 50-seaters at Pinnacle depends on what rate Delta pays for them and how much Pinnacle can lower its costs, says Ray Neidl, a Maxim Group analyst.

“There still will be a need for 50-seaters, just not as many as are out there [now],” Neidl says. The 50-seater is not a growth market, he adds, “but at this point in time they [Pinnacle] are just trying to survive. Their fate is in the hands of Delta and, I guess, their employees.”

The newly revised contracts with Delta for the operation of the CRJ-200s and 41 CRJ-900s modifies the rates paid by Delta and eliminates the 2013 rate reset and pilot rate reset, which would have increased the amount of Delta’s payments.

Those pilot rate resets were going to be based on pilot pay raises that Pinnacle is seeking to eliminate under its bankruptcy restructuring. That makes the outcome of Pinnacle’s negotiations with its employee labor unions even more important—or, absent a voluntary deal, a Pinnacle request for the court to allow a rejection of the existing agreements and imposition of new terms.

Tom Wychor, chairman of the Pinnacle Master Executive Council (MEC) for the Air Line Pilots Association, said April 2 that union members “are always willing to sit down with management to find solutions to actual problems,” but he adds that “these solutions need to maintain contract standards that make this a career worth having.”

Pinnacle is planning to meet with members of the MEC next week.