+0

What’s the difference :

I should be able to pick you up from the airport.

I could/can pick you up from the airport.

+1

I should be able to pick you up from the airport.

This implies that there may be some future difficulty, but probably not..

eg I should be able to pick you up from the airport. as long as there are no traffic jams.


I could/can pick you up from the airport.

This sounds more definite.

Clive

+1

I should be able to pick you up from the airport. Probably I will be able to pick you up, but I can't promise you I will.

I could/can pick you up from the airport.

I could pick you up from the airport. (This is a suggestion, an offer, or a possibility.)

I can pick you up from the airport. ( I am totally available and able to pick you up from the airport.)