WASHINGTON, May 7 (Reuters) - The CEOs of the five

largest U.S. airlines on Thursday plan to back the Trump

administration's plan to spend tens of billions of dollars to

reform the aging air traffic control system and boost hiring,

officials said.

Delta Air Lines ( DAL ), United Airlines, American

Airlines ( AAL ), Southwest Airlines ( LUV ) and JetBlue Airways ( JBLU )

chief executives are all expected to speak at an event

Thursday in which Transportation Secretary Sean Duffy will

detail his proposal to Congress.

Also expected to attend are some relatives of the 67 people

killed in the Jan. 29 mid-air collision of an American Airlines ( AAL )

regional jet and a U.S. Army helicopter near Reagan Washington

airport.