Air travel and little dogs, how do i make it the most comfortable?

I will be bringing my little Norwich Terrier on a trip to Denmark. We will take off from San Francisco to New York and then from New York to Denmark.
The total travel time is 15 hrs, 5 and 8 hours plus some overlay time.

He will be sitting with us in the cabin in a special carrier. What can i do to make the flight time the most comfortable for him?

have a blanket in there and some stuff for him to chew on and play with

First call your airline and make a call to the US embassy in Denmark to find out what the paperwork requirements are. Your dog will need an international health certificate to travel. The exam and paperwork usually needs to be filled out by a veterinarian no more than 10 days prior to travel. Each country has different requirements for pets entering the country. Some only require this certificate and others require more paperwork. Very important to call the embassy and find out. You would hate to get to Denmark and find out your beloved pooch is not allowed in. Talk to your vet at this appointment. He/She may be able to prescribe a mild sedative for the flight. The layover is a great thing. Pain in the neck for you but if will give your dog time to go potty and get some exercise.

He will need a long walk in NY. Check with the airline to make sure you have ample time to do this.
Your vet can give you information about air sickness and a possible sedative in case he gets too upset during the flight.
Take him in the bathroom of the plane and let him out. Take some piddle pads for the flight. Make sure he has plenty of water during the trip, but limit his food intake.
Put one of his favorite toys in his carrier with him.
Have a great trip. Hope this helps.

Ask your vet for a tranquilizer. This is not an unusual request and he'll just give you however many is needed for the trip. Just pop it in a piece of hot dog or cheese and give it to him about a half hour before boarding. He'll not be "knocked out," just pleasantly sleepy and calm. It will be much less traumatic for him.

Maybe you should call the airline and find out if you can take your dog out of it's cage. If not make sure that your dog is entertained with bones and toys. You might even want to take a blanket or two so your dog can sleep.(It will most of the time.)