A $6.9 billion surplus in an aviation trust fund that is entangled in budget-balancing contrivances would be released to pay for devices to detect plastic explosives in airliner luggage, under legislation before a House committee.

The administration already has ordered airlines to buy and install $1 million thermal neutron devices in high-risk U.S. and foreign airports, even though the method of payment is not settled.The first thermal neutron device, which detects plastic explosives by bombarding luggage with neutrons, is to be installed at John F. Kennedy International Airport in New York in July.