Bids for the alternate systems are due by June 8, with the Air Force expected to award a contract in September.

Boeing won a $235 million deal to develop the new terminals in September 2002, but the program’s cost has risen sharply since then. The Air Force’s fiscal 2013 budget proposal asked for $107.5 million to continue work on the FAB-T program, less than half the 2012 sum of $231.2 million.

In February, Major General John Hyten told reporters that the Air Force would proceed with the alternate source program regardless of how the talks with Boeing turned out.