Last year we left our Hotel (Newport Bay) around 6:30pm, our flight home was 21:20 and we checked in at the airport at 7:15pm. This wasn't planned, we had arranged to get the 5pm bus because my son was getting anxious, we actually couldn't get on two VEA's (even after being told to put our luggage on one and then had to quickly take it off!) and at the time thought it a little unfair that all people with prepaid tickets were being left until those who wanted to pay had gone on, then it meant that the bus was full! I wasn't too bothered as I knew we'd left plenty of time before our last check in, but it's worth thinking about that happening, although this was August and therefore the busy period.
I think the advice the hotels give is to get the VEA that is two hours before your check in time.
We found the journey last year to be around 30 minutes, our bus seemed to take us a different way than in previous years where it had taken 40 - 45 minutes.
Because of our experience last year, we have decided to book a private shuttle for this year, that's next on my list to do!!