First, establish exactly how your dog will travel
Flying with a dog is not one experience but two very different ones: small dogs may travel in a carrier in the cabin with you, while larger dogs travel in a ventilated hold in an approved crate. The preparation, paperwork, and stress points differ, so confirm with the airline before anything else which applies to your dog, what carrier dimensions and total weight are allowed, and what health documents the route requires. Book the dog's place explicitly rather than assuming a ticket includes him, and check rules for both directions of the journey, since the return leg can fall under a different country's requirements.
Make the carrier a bedroom long before it is transport
The single most effective preparation is turning the carrier or crate into a familiar resting place at home. Leave it open in a room he uses, with his bedding inside, and let him choose to nap there for weeks before the flight. Feed occasional meals in it, close the door briefly while he is relaxed, and practise carrying or wheeling it short distances so movement inside it is not new on the day. A dog who walks into his carrier willingly at the airport has already won half the battle; a dog meeting it for the first time in a check-in queue has been set up to panic.
Rehearse the sounds and sensations you can simulate
You cannot practise the flight itself, but you can blunt its novelty: play recordings of crowd and aircraft noise quietly at home while he rests in the carrier, take him through busy places if he copes with them, and get him used to being handled and briefly examined by unfamiliar people in case of security or vet checks. Visit your vet in good time for the required health certification and to discuss your individual dog — age, breed, breathing, and temperament all affect whether flying is advisable at all, and brachycephalic dogs and others with breathing compromise face particular restrictions and risks that a vet and the airline must weigh honestly.
Run the travel day on a calm, early timetable
Exercise him well before leaving for the airport so he boards tired rather than wired, give a light meal well ahead of the flight rather than a full stomach, and allow a final toilet opportunity as late as possible. Arrive with time to spare: rushing handlers make rushing dogs. If he travels in the cabin, settle the carrier under the seat and keep your own behaviour quiet and boring. If he travels in the hold, attach clear identification and your contact details to the crate, confirm with staff at the gate that he has been loaded, and tell the cabin crew he is on board so any concerns reach the right people.
Help him land, not just take off
On arrival, get him out to toilet, water, and solid ground as soon as rules allow, and keep the first hours low-key with familiar bedding and food rather than sightseeing. Watch his appetite, breathing, and behaviour over the following day; most dogs bounce back after sleep and a normal routine, but persistent distress, breathing difficulty, or refusal to eat or drink warrants a vet. When every certificate, vaccination record, and vet note for the trip sits in your KinsLe Pet Passport as one portable packet, the document checks at each end stop competing with your dog for your attention.