Wordnet 3.0
NOUN (2)
1. 
 a flighty scatterbrained simpleton; 
- Example: "she's a total airhead"- Example: "every airhead on a big salary rushed out to buy one"2. 
 a bridgehead seized by airborne troops; 
The Collaborative International Dictionary of English v.0.48:
airhead \air"head`\ ([^a]r" h[e^]d`), n.
   an airheaded person. [disparaging]
   [PJC]
WordNet (r) 3.0 (2006):
airhead
    n 1: a flighty scatterbrained simpleton; "she's a total
         airhead"; "every airhead on a big salary rushed out to buy
         one"
    2: a bridgehead seized by airborne troops