The groundings will accelerate the shift of inventories toward asset managers and leasing companies, especially global ones. Cash must be available and shrewd judgments made to exploit opportunities and control exposure.

Grounded jets returned to service will demand parts, although with different carriers in different regions. Torn-down jets boost part supplies, softening prices. Boeing 737 Classics will find better flying opportunities than MD-80s.

Eric Mendelson, CEO of PMA maker HEICO, speculates that two-thirds of 737 Classics will fly again, but only half of the less fuel-efficient MD-80s will. Nathan Dalton, sales VP at Wencor, thinks most 737 Classics with CFM engines will continue to fly, but MD-80s will shrink toward fewer operators, like 727s.

Matt Eaton, VP at FlightStar Aircraft Services, sees many 737 Classics parted out now. "It's a high-number, high-cycle airplane, built before aging aircraft and cycle-fatigue knowledge," Eaton noted.

John Brooks, VP Airframe Division at Volvo Aero Services, also is pessimistic. "I don't think most Classic 737s will return to service. Perhaps 25% will go to Africa and South America. The rest will be parted out or scrapped."

Sean Flannery, head of the Asset Services Group at GECAS, says 737 prospects depend on age and condition. "After 50,000 cycles, they are very expensive to maintain." But fresher Classics are only 5% less fuel efficient than NGs. "We see demand in Russia, Indonesia, Saudi Arabia, Pakistan, Tanzania [and] Nigeria, as well as some cargo demand." The less efficient MD-80 does not have much of a future if fuel prices stay high, in his view.

Tom Wilson, VP Component Solutions and Business Development at Aveos (formerly ACTS), also sees conversion prospects. "Many 737 Classics will go to China's Pearl River, and some to airlines that Boeing cannot supply with NGs. At least 50% should return somewhere." But MD-80s with heavy airframe and engine work due have grim prospects.

Richard Ching, president of Palm Aerospace, expects American Airlines to ground its oldest MD-80s first, so these will be torn down. But Ching hopes that many MD-80s will fly again, pointing to carriers like Allegiant Air that fly MD-80s exclusively.

Ching thinks both older narrowbodies will go to second- and third-tier carriers in Latin America and Africa. Conrad Vandersluis, maintenance director at A J Walter Aviation, sees many 737 Classics flying in Russia and Eastern Europe.