The former United and Scotland captain has stepped up to lead the U18s after a coaching shake-up inside Carrington.
Fletcher began with a 1-0 win at Everton on Saturday.
He told manutd.com: "I’ve really enjoyed it.
“From the first time together in Germany at the adidas headquarters, the boys have been fantastic. We had pre-season games at Carrington and then we went to Zagreb, and the performance levels, the attitude, the application, in every game, they’ve been a real pleasure to work with so I’m really enjoying it.
"It’s nice to lead, to be in charge of your own team. I was always in a support role before, so I felt that for the next stage of my development as a coach, it was important that I led a group, and with Adam Lawrence leaving, the opportunity became available and it made sense from a number of reasons.
“I’m really excited to be on the grass every day, working with the team, implementing Manchester United’s style, club ideas alongside some of my own ideas and it’s been really enjoyable. And the most pleasing thing has been the players’ application and buy-in into it and I’m really enjoying seeing them play the United way.”
Like sponges
Of how he plans for his United team to play, Fletcher is eager to ease expectations around his squad.
He also stated: “It’s important we let them develop.
“They’ve got loads of development to do but they’re sponges. They want to learn. They’re young boys who just enjoy football. They take on the information, we’re trying to give them a platform on which to express themselves.
“And we have to recognise their age as well. We don’t want them to grow up too quickly. Let them just develop. It’s difficult when they’re on TV, but that’s part of the game and the modern world. We don’t want to hold anybody back. If you’re performing, you’re going to get rewards for it. They’ve played because they deserve it and they’ve shown they can compete and fight at this level.