Airbus and Boeing supremacy secure

FARNBOROUGH, United Kingdom — Boeing's safety troubles and the Airbus scramble to ramp-up production should have left a gap for smaller rivals to challenge their domination of the commercial airliner market.

Yet the American and European giants face little near-term threat to their lock on the medium- and long-range aircraft markets, industry experts say, as the barriers to entry are too high for China's Comac or Brazil's Embraer.