As President Trump pushes for the Pentagon to buy more of Boeing Co.’s F-18 aircraft, the Navy is grappling with an escalating problem: pilots suffering potentially dangerous oxygen deprivation or a loss of cabin pressure in the fighter jets.

All F-18 models, including the Super Hornet that Trump has championed, have shown steady annual increases in what the Navy calls ‘‘physiological episodes,’’ according to service testimony obtained by Bloomberg News. What’s more, the data show that incidents of oxygen deprivation and cabin decompression have escalated in the last year, while service officials work to determine the root cause of the in-flight problems.

Trump’s promotion of the Super Hornet began in December with a tweet. Translating Trump’s request into action, Defense Secretary James Mattis commissioned a review of improvements that would ‘‘provide a competitive, cost effective, fighter aircraft alternative’’ to the F-35C, the Navy version of Lockheed Martin Corp.’s Joint Strike Fighter.

‘‘Since May 1, 2010, all models’’ of the F-18 ‘‘show steady, yearly increases in the number of physiological episodes,’’ a staff memo prepared in advance of a hearing Tuesday of a House Armed Services subcommittee said. Navy officials testifying before the committee called the problem the ‘‘No.1 safety issue.’’

‘‘I am concerned about this growing trend — one that has a significant effect on readiness and one that needs to be fixed,’’ Representative Mike Turner, the Ohio Republican who leads the Tactical Air and Land Forces subcommittee, said in his opening statement.

Despite good-faith efforts, the ‘‘lack of overall progress’’ is ‘‘of great concern,’’ said Representative Niki Tsongas of Massachusetts, the panel’s top Democrat.

Bloomberg News