I was wondering about this too. I went to another island to get a diy from a villager. When I went back to the airport I couldn't leave. I tried repeatedly and the game suggested it was because someone had a window open but the island resident was afk and no one else was there. I had to use - to leave and then i had to go back again cause I lost the diy. When I went back I could see something was wrong cause there was a player character by the airport and it kept like skipping cause the connection was bad. Luckily I got the diy and had no issues going back that time.