WASHINGTON — Updated July 25, 2018: This story has been updated with a response from the East Wing. Read more coverage about the first lady.

On the first couple’s recent trip overseas, Melania Trump’s television aboard Air Force One was tuned to CNN. President Trump was not pleased.

He raged at his staff for violating a rule that the White House entourage should begin each trip tuned to Fox — his preferred network over what he considers the “fake news” CNN — and caused “a bit of a stir” aboard Air Force One, according to an email obtained by The New York Times. The email, an internal exchange between officials in the White House Military Office and the White House Communications Agency last Thursday, also called for the ordering of two additional televisions to support Beam, a TiVo-like streaming device, to make sure the president and first lady could both watch TV in their separate hotel rooms when they travel.

At the end of the email chain, officials confirmed that tuning the TVs to Fox would be standard operating procedure going forward. On Wednesday, Mrs. Trump’s spokeswoman issued a statement to CNN saying that the first lady watches “any channel she wants.”

The channel-flipping flap was the latest example of how Mr. Trump, at a pivotal moment in his presidency, is increasingly living in a world of selected information and bending the truth to his own narrative. As his aides work to keep him insulated from the outside world, Mr. Trump is doubling down in his efforts to tell supporters to trust him over the words of critics and news reports.

For now, his approach is working: His standing with Republicans continues to rise, according to a series of new polls.

“Stick with us. Don’t believe the crap you see from these people, the fake news,” Mr. Trump said Tuesday at the annual convention of the Veterans of Foreign Wars in Kansas City, Mo.

And then: “What you’re seeing and what you’re reading is not what’s happening.”

Similarly, as the negative headlines continue after Mr. Trump’s meeting in Finland last week with President Vladimir V. Putin of Russia, Mr. Trump has shifted from blaming American institutions for a bad relationship with Russia to telling people not to believe the facts of what they have seen or heard.

On Tuesday, the president effectively said black was white when he claimed without evidence that Russians would be helping Democrats — but not him — in the coming midterm elections. In January 2017, American intelligence agencies assessed that Russia had interfered in the 2016 presidential election in an effort to help Mr. Trump.