How long a drive is it from Oxford University to Stansted Airport?
Absolute minimum of 110 minutes but you would be wise to allow for rather more than this. Involves driving on the M40, M25 and M11. Cross country route would be more than 3 hours. The bus from Oxford going that way takes 4.
Sharon - I'll add to what Marco just said. The M25 particularly can be an absolute nightmare. Some parts of the day, its closer to a parking lot than it is a motorway. For reference, by train, National Rail is showing roughly 2 hrs, 54 minutes. Thats Oxford into London Paddington, Tube over to London Liverpool Street Station, then train to Stansted.