Over the years, Airbus Industrie has taken plenty of flak from U. S. rivals such as Boeing Co. Now, it's shooting back. Miffed that British Airways PLC buys only American planes, Airbus is charging illegal sales tactics and has demanded a European Community probe. Airbus claims BA got a disguised rebate from engine builder General Electric Co. on an August order of Boeing 777s. Yet Airbus says that GE, in cahoots with Boeing, refused discounts on engines for Airbus. Airbus may be trying to muddy Washington's marathon talks with the EC on limiting Airbus' government funding. EC bureaucrats are skeptical, saying it will be tough for Airbus to prove the charges.