Did you perhaps not put good pilots on it? Little Bird can stand up to most early game vessels. Bandit Car, Bandit Wartruck, Highway Convoy, Sandcrawler, Rogue Courier, Highwaymen Hoverpod, Black Helicopter, etc... probably also Bandit Zeppelin with two weapons and good pilots. I think Necroplane is too strong for it, and Ninjas will obviously wreck it. Anyway, put XTRA ARMOR on it if your pilots are crap and only use CHEM-TANK if you got no choice.
The main benefit of Little Bird is the hidden 12x Glamour that you get on ground missions with it. This glamour also gives up to +144 additional mission score. Well, assuming you can finish those missions before the glamour decays.