Arsenal star Sanchez is understood to have agreed £500,000-a-week deal with United.
He was thought to be in Manchester preparing for his medical.
But the player posted a video on his instagram account this morning, appearing to show him boarding a plane at a snowy airport.
Sanchez is all set to undergo a medical later today at United’s Carrington training base.
Express Sport understands he has not yet arrived for the physical tests.
Meanwhile, Henrikh Mkhitaryan was spotted in London last night ahead of his move to Arsenal.
The Gunners and United have agreed a straight swap deal between the pair.
More to follow…