President Trump said Saturday that he has reduced the price of two new Air Force One planes by more than $1 billion after spending about an hour on negotiations.

Trump previously slammed the cost of the $4.2 billion Boeing program on Twitter as being too high and secured a personal promise from Boeing CEO Dennis Muilenburg to complete the program for under $4 billion.

"I refuse to fly in a $4.2 billion plane," Trump said at his Melbourne, Fla., rally. "We've got that price down by over $1 billion and I probably haven't spoken for more than an hour on the project. I got the generals in who are fantastic … but I told Boeing that isn't good enough, the price is still too high."

Trump also suggested that the country may not buy two Air Force One jets that would replace the two current planes.

"Why they need two planes, we'll have to talk about that," he said.

Trump also spoke about the "disaster" program with Lockheed Martin to build the F-35, which he has repeatedly slammed on Twitter for its "out of control" costs. He said the prime minister of Japan, Shinzo Abe, whose country is an international customer for the F-35, personally thanked Trump for saving "many millions of dollars" on the program when the two met this month.