Why is it lacking so much? Your FPS must be 10 to 15 right?
You mean a lag in some spots?! Yes there's some. But as for the FPS I'm not sure. 
Your lag is actually quite severe. To see your FPS, just hit Shift-Z twice and it will be in red text, top right. I'd imagine your's are around 10, which especially for a video, is brutal. Perhaps that's why your takeoffs are far too steep in degrees you point the nose upward? It lags and you over-correct?