A source told the Sunday Mirror: 'It's traditional that guys on his course, which is split between California and Arizona, have a break in Vegas at the halfway point.
'The course doesn't have much downtime, it's pretty intense. This is a chance for pilots to let their hair down, kick back and enjoy themselves.'
As part of his US training, Harry - who was recently promoted to a Royal Air Force Captain - will learn how to use weapons systems on board a helicopter and take part in mock combat missions with American forces.
He will also be taught techniques which will help him avoid surface-to-air missiles.
Harry recently enjoyed a holiday to Croatia, where he even jumped into a pool fully clothed at an open air nightclub on the island of Hvar.
