On 11 April 2017, the entertainment web site News Thump published a satirical article reporting that President Trump voiced support for United Airlines after a video surfaced showing a passenger being forcibly removed from a flight:
President Trump has been quick to herald United Airlines staff and security as ‘my kind of people’ after footage emerged online of an elderly foreign-looking doctor being violently thrown off a plane.
[...]
President Trump addressed White House press shortly afterwards saying, “Listen people, what United Airlines did today was great, just great. These are the kind of things that will help make America great again, bigly.
“They told this guy to volunteer to give up his seat, and he refused. Sad! So un-American.”
This is not a genuine quote from President Trump. News Thump is an entertainment web site that does not publish factual stories. The web site's disclaimer says it is a "satirical and spoof news website":
We are not afraid to skip a few steps like checking facts or corroborating sources, and we never let the truth ruin a funny story (it’s much easier just to make everything up). So, for clarification – If you read a story on here, then you are NOT supposed to believe it. It has been completely made up purely for entertainment purposes. It’s also worth noting that we regularly use rude words and stuff, so you need to be 18 to be reading this. All images are courtesy of iStockphotos/Getty and are used for illustrative purposes only, and anyone depicted is a model.
In addition to the fake news article, an image purportedly showing a tweet from President Trump voicing his support for United Airlines circulated on social media:

This is not a real tweet from Trump; the tweet was posted as a screenshot, which can be easily manipulated, with no link to an original tweet. It does not appear in Trump's Twitter timeline, or in any genuine news reports. Nor does it appear on the page where ProPublica, an independent news outlet, monitors his deleted tweets. Further, if the tweet were genuine, multiple retweets would be available on Twitter, but we could not find a single one.