If you can't see the pitot tube put the cover where you can see it, or reach it, to confirm it's off !
NEVER go flying when you didn't intend to in the first place ! Sounds daft, but I have a VW engined microlight that is a bastard to start, hadn't flown it for awhile so decided to ground run the engine, eventually got the thing running and it sounded sweet, the wind had dropped, around 30 mins of useful daylight left, so what the Hell, lets do a circuit. Immediately after take-off I was doing 140 knots, Vne is 104, and climb speed normally around 60 kts. Pitot cover still in place ! So...wasn't stalling, so push the nose down a bit to be safe, level off at circuit height, set normal power for cruise and approach, s'easy - but it makes you think, even after 21k + hours aeroplanes will still bite.
On aeroplanes with check lists, if interrupted ALWAYS start again at the top, maybe not necessary to re-do everything, but at least read it in sequence, otherwise Mr. Murphy will quietly ensure that you re-start at least one item below where you stopped.
