Is it reasonable for a girl to let her boyfriend pick up the plane?

Since you asked him to pick up the plane, it means that you are going to visit him in his city. It is reasonable to ask for pick-up.

First of all, whether you visit him in his city or not, he should come to see him. He is your boyfriend. It is normal for him to pick you up unless he has more important things to do. If his business is really serious, don't let him pick you up again. Have priorities. You can find your own hotel or something, so don't delay his activities. Even if you can't find it, you can take a taxi to help you find it.

Second, if you go to his city, he will come to see you at the airport at first sight anyway. Many long-distance lovers, one side goes to the other city, and the other side always meets at the station or airport. Because they want to meet their lover at the first sight, they will appear no matter how late. If you want to meet him as soon as you get off the plane, he must feel the same way, so don't be too cautious. Let him pick you up and take a look at you to satisfy the feelings of two people.