Facing a midnight Tuesday deadline, U.S. and British negotiators tried unsuccessfully again yesterday in London to work out a new agreement governing scheduled air services between the two countries.

Without a new agreement in place, it is possible that scheduled air services between the two could be halted after 12:01 a.m. EDT Wednesday. The scheduled American carriers have in place contingency plans that would take travelers first to other cities in Europe and then provide them with alternate transportation into England. British Airways plans to take travelers to the U.S. into Canada should it need to.

Charter flights would not be affected.

Yesterday, Transportation Secretary Brock Adams insisted there would be no extension of the deadline. "We are holding to the position there will not be any [air] rights if we can not get agreement by midnight Tuesday," he said. But he said if negotiators can reach general agreement on outstanding issues before the deadline, service may not be cut off.

The British denounced the existing agreement a year ago, hoping to negotiate a new one that guaranteed British carriers exactly half of the traffic between the two countries. The U.S. carriers currently carry almost two-thirds of the traffic.