Dave
I'm sure you'll love San Diego. Beautiful, wonderful atmosphere and widely regarded as the best climate in America - hot, but not too hot, and rarely humid.
Some suggestions -
La Jolla, the jewel in San Diego's crown - about 20 mins North of downtown.
Very pretty, an affluent area but with a down to earth atmosphere, good beaches each with a different character, lots of interesting shops (no big stores) and some excellent restaurants.
Mt. Soledad Veterans Memorial, about 5 mins drive from the centre of La Jolla.
The views are spectacular in every direction.
Some protest groups have been trying to have the Cross removed
but they haven't succeeded yet (32 years) so I'm sure it will still be there in September. (The protesters have won most technical legal arguments in the long-running court battle but the City of SD, supported by the overwhelming majority of SD voters, is equally determined it should stay so the fight goes on - and will probably end up in the US Supreme Court eventually.)
Coronado - a 10 minute drive from downtown, over the 2 mile long Coronado Bridge.
Very pleasant beach - and usually a good selection of military aircraft passing overhead to and from the nearby North Island Air Station. The famous Hotel Del Coronado, reputedly one of the oldest and biggest all-wooden buildings in California, has featured in many movies.
Tijuana - about 17 miles.
A tourist trap in many ways, but still an interesting experience IMHO.(Mexican food is better in San Diego.)
The easiest way to get there is probably the San Diego Trolley but, if you want more flexibility, drive to the border and leave your car in the parking lots on the US side. Most (all?) rental companies don't allow cars to be taken across the border.
USS Midway Link
If you're going at the end of September, that coincides with the annual Miramar Air Show. Miramar is now a Marine Corps Air Station but is best known as the former home of the US Navy Fighter Weapons School - made famous by the Top Gun movie.
I haven't used any flight schools recently so can't offer any recommendations but there are several at the two GA airfields I mentioned in my previous post. I've tried various schools over the past 30 years and have always been satisfied.
Have a great time.
FL