1.   But talk that the Concorde has outlived its usefulness has persisted, and no other supersonic jetliners are in development.

2.   He spends his spare time working on a design for a supersonic jetliner.

3.   It was originally thought to be too big, and Boeing never expected to sell many before supersonic commercial jetliners stole the market.

4.   A Concorde supersonic jetliner has been donated to the museum but remains in France until facilities are available to accommodate it.