It isn't uncommon to have several airplanes in the air at one time. In fact, its pretty normal. Just because they are flying doesn't mean that you have to wait for them to land. You can fly at the same time .
If you are uncomfortable flying with other planes in the air, then say so. Most people would not assume that. They just don't realize you would rather fly alone. I'm sure that you could mention your "comfort" issue to them and they would understand.