1. To have someone or something travel to one via airplane. In this usage, a noun or pronoun can be used between "fly" and "in." Did you hear that the school is flying in a well-known author for the literary festival?

2. To travel to a particular destination by airplane. I'm flying in on Thursday—can you pick me up at the airport?

3. To travel to a particular destination by airplane. I'm flying into Philly on Thursday—can you pick me up at the airport?