Ryanair (FR, Dublin International) has threatened to cancel its hefty B737 MAX order and look at alternative manufacturers if tariffs threatened by US president Donald Trump make the Boeing narrowbodies more expensive, Reuters reported.

In a letter to US lawmaker Raja Krishnamoorthi, a Democrat from Illinois, Ryanair Group CEO Michael O'Leary said the LCC would "reassess both our current Boeing orders and the possibility of placing those orders elsewhere", including with Chinese aircraft manufacturer COMAC.

According to Reuters, O'Leary was responding to an April 29 letter from Krishnamoorthi in which he warned Ryanair against buying COMAC aircraft over security concerns, claiming that the Chinese firm has close ties to the Chinese military and that it may have "illegally acquired" foreign intellectual property.

In his reply, O'Leary reportedly said the LCC had not discussed potential aircraft orders with COMAC since 2011 when it it signed a cooperation agreement with the manufacturer to assist in the design of a new narrowbody. He said, however, that the LCC would consider an order if the units were 10-20% cheaper than Boeing rival Airbus.

COMAC has not yet received any orders for its C919 narrowbody, which is similar in size to an A320 or B737, from any airline outside China. The European Union Aviation Safety Agency (EASA), meanwhile, has poured cold water on the manufacturer's claims that the type would be certified in Europe in 2025, saying that certification could take three to six years to complete.

Ryanair currently has twenty-nine B737-8-200s and 150 B737-10s on order from Boeing. O'Leary warned in April that the LCC could delay the deliveries of the new narrowbodies if the proposed tariffs cause a price hike.

Meanwhile, Ryanair, which expects to take delivery of fifteen B737-10s in 2027, recently made a deal with the planemaker for it to deliver further B737-8-200s if the largest variant of the MAX family does not receive certification by the end of 2025.

ch-aviation has contacted Ryanair and Boeing for comment.