Getting your pet used to a crate is one of the most critical but largely underestimated activity. We highly recommend getting your pet used to the crate at least 8 weeks before the travel.
Your pet should be comfortable such that she/he is sleeping in the crate for at least 8 hrs during the nights leading to the travel
If this is accomplished, this crate will serve as her/his little home and the stress of flying is reduced by a large extent.
Its also important to get your pets (especially mid/large/giant sized dogs) to go into their crate voluntarily since they will be required to taken out and required to go back into the crate a few times at the airport before boarding.
And this the the most likely place that they will decide not to go back into their crates!
Get your pet acclimatised to the crate from our experiences listed in our Crate training document ( Download here ).