Synonyms of airheadedness

2 Syllables
lightness
3 Syllables
fickleness, dizziness, flippancy, flightiness, giddiness, levity
4 Syllables
capriciousness, whimsicalness, frivolity, inconstancy, mercurialness
5 Syllables
changeability, volatility, whimsicality, instability, variability