He also rejected the conclusion of United States intelligence officials who had said Russia was behind the hacking of the Democratic National Committee and Clinton campaign emails released on WikiLeaks, saying he thought that conclusion was driven by politics.

“I don’t believe it. I don’t believe they interfered,” Trump said of the Russians.

The interview came as Mr. Trump continued to fill out the ranks of his administration with loyalists who will play pivotal roles. He told donors at a private fund-raiser at the restaurant Cipriani in Manhattan that Terry E. Branstad, the governor of Iowa and an early supporter of his campaign, would be the United States ambassador to China, a crucial post managing a complex relationship that Mr. Trump has indicated he is willing to shake up even further.

Mr. Trump also said he would have more “big announcements” on personnel on Wednesday and Thursday.

Another contender for secretary of state, he said on “Today,” is Rex W. Tillerson, the president and chief executive of Exxon Mobil, whom he called a “great, great gentleman” who has “built a tremendous company over a period of years with great style.” He said he had ruled out “in my own mind” other prominent candidates who have been considered for the post — a group that includes Rudolph W. Giuliani, the former mayor of New York; Gen. David H. Petraeus, the former C.I.A. director; Senator Bob Corker of Tennessee; and John R. Bolton, a former ambassador to the United Nations — but he declined to say which ones.

One day after picking a fight on Twitter with Boeing over the cost of developing the next generation of Air Force One, Mr. Trump said he had spoken to officials at the company and would insist on a lower-cost aircraft or cancel the contract.

“We’re going to work it out, but you know that’s what I’m here for,” Mr. Trump said. “I’m going to negotiate prices, and the planes are too expensive, and we’re going to get the prices down, and if we don’t get the prices down, we’re not going to order them.”

He also explained his apparent decision in June, divulged by a member of his transition team on Tuesday, to sell all of his stock holdings, a move he said he made to avoid “tremendous” potential conflicts of interest in the event he won the election.