I have a similar problem Frank - my Nexus 7 never picks up the GPS signal until I'm well into my flight, even with the 3G running. I've had to resort to my tiny Samsung phone to track my route running SD on a number of occasions. I haven't worked out yet where the problem is....

Same problem with Asus fonetab. Crash a lot of time. I can't used it by flying.
On my phone Galaxy S3, no problem!