Richard Aboualfia of AeroDynamic Advisory said a delay of Max 10 certification could push customers into the arms of European rival Airbus, further eroding Boeing's 40 per cent share of the narrowbody market. United Airlines CEO Scott Kirby flew to Toulouse recently to inquire whether it could buy A321neo jets to replace Max 10 order slots, Reuters reported on Sunday. Dennis Tajer, a spokesperson for the union representing American Airlines pilots, said Boeing's decision to withdraw the exemption request was good news, but questioned what Boeing and the FAA would do for the Max 8 and 9 models. "What are they doing about the planes that are flying now?" he said. The FAA said last year Boeing was developing a design change to fix the problem on the Max 8 and 9 and it might require it to put it in place on those planes in the future. US Senate Commerce Committee Chair Maria Cantwell said Boeing's withdrawal "is good news.