We always use the economy lot at the airport. Hubby drops us off at curbside check in with our luggage and we all get our boarding passes. Then he takes the car to the econ lot while the kids and I walk around the airport. The shuttles run every 10-20 minutes except at really odd hours. We always take the 6:15 am flight (arriving at the airport at 4:45am) and it never takes longer than 30 minutes for my husband to drive down, park the car, and catch the shuttle back to the airport. Coming back, we pick up the bags, then the kids and I park ourselves out on the curb (always need fresh air after flight) and then hubby hops on the shuttle, gets the car, and drives around to pick us up.
You can take luggage on the shuttle, so if you don't have that much, or if your kids are older you can just go to the lot together. But we have 3 small kids which means lots of luggage, stroller, car seat for plane, etc., so hubby drops us off.
My husband doesn't like leaving the car with anyone, esp. with the keys. And he leaves his car at the airport all week, every week (we live in Bucks co and he works in California--don't ask) and he's never had any trouble.
Jenny