SportPet Designs Airline Approved Plastic Dog Kennel, Small

We purchased five kennels searching for the appropriate one for our cat to go on the plane for our move to Spain. Per the IATA crate guidelines, dogs can have openings that are a maximum of 1 in x 1 in, but cats must have 3/4 in maximum openings (19 mm x 19 mm). The measurements of the grated door's spacing (and the ventilation openings on the sides of the kennels) were not provided on any of the listed kennels we purchased, but I can confirm that the small size of this brand has 3/4 in openings. The medium size for this brand has 1 in x 1 in. The frustrating part is that our cat (fairly regular sized) is 15 inches tall. This size is 15 3/4 in height. While we would have liked to give him a few extra inches of headspace, the medium sizes of all crates we purchased had 1 in x1 in openings. The good thing about this brand is that it's a little over 15 in for height, so at least it was a tad extra for our cat compared to the other options (that had 15 in heights for their small kennels). It also came with metal bolts and nuts and felt more secure than the other brands. We had one other kennel that had the appropriate sizing, but it didn't have zip tie holes, so I would recommend this one over SkyKennel for that reason (plus the extra 3/4 in height).