Planes

You have likely already experienced the San Diego Airport. As far as airports go, it's pretty good, but it's definitely in the shadow of the Los Angeles Airport (LAX), meaning it's not as major an airport as one might expect for a city the size of San Diego. It's possible to bus from campus to the airport for $2.25 (take 992, switch to 41 downtown), but it's not easy and will take you about two hours.

Another alternative are the various for-hire shuttle services: $20 will get you to campus, which is cheaper than a taxi.

Nonetheless, you're likely better off finding a different route there (ideally a ride with a friend).