I think Airtours fly from most regional airports. Last time we flew "direct" from Manchester they whisked us off to Newcastle to pick up more passengers adding over an hour to the flight time. Nobody bothered to tell us until we were on board.
The easiest drive from Sanford Airport is down the Central Florida Greenway, which is a toll road and then turn off on the 536 which takes you straight into WDW. Tolls cost about $6, driving time about 30 minutes.
The alternative is Interstate 4 which is free, but has very heavy traffic at times and could take you twice as long to get to WDW.
If you're a first time driver in Florida, take the Greenway.