Wide Aircraft Cockpit Photography Advice.

So, after getting my new Canon 10-22mm I decided to take it to take it to work and shoot some "office" shots. Hand-held, on my 50D I used Av mode with f3.5-4, at 10mm and tinkered with the ISO between 600-1600, in one of the pix I used the internal flash. All pix came out blurry and noisy! The sky was overcast so not much ambient light was available. I turned the dome light on/off and even turned all the displays/overhead lights on - still blurry. Should I have brought my Canon 580exII external flash, possibly using Manual mode with ISO around 800? Or do I need a tripod and long exposure, for these types of shots? Any hints/tips/suggestions are greatly appeciated.

I'd like to avoid bringing my tripod, as i already have enough baggage to lug around!

Shooting wide outside, daytime/sunny is no problem for me ISO100 and f8-11 seem to work fine in Av mode - but close quarter, dimly lit cockpit are a challenge so far. Granted this was day one with the new lens.