Air Travel Baggage: Rucksack Dimensions - Will squashing it down to the size of dimensions be okay?

Question

If perhaps my Rucksack is a few CM larger than the dimensions by design, but I can compress it into the dimensions because of the room left inside 3/4 full, will that be okay?

Or will Ryanair ensure they measure it according to the way it was manufactured. It is just a standard issue rucksack, not large at all by any means.

I know what these cheap airlines are like and I will probably lay some serious mushroom clouds with my anger if they try and turn me away.

Answer 1

I don't know about Ryanair but with Northwest as long as it's flexible and you can smoosh it in there you're good to go! :o)