Synonyms for Flighty (same or very similar meaning)
WordNet sense 1 (guided by whim and fancy):
scatterbrained, flyaway, head-in-the-cloudsWordNet sense 2 (not serious in content or attitude or behavior):
frivolousWordNet sense 3 (unpredictably excitable (especially of horses)):
nervous, skittish, spookyWordNet sense 4 (easily excited):
excitableFrom the ODE community, based on WordNetadd/edit