A carrier is a must-have for cat travel, but getting stubborn cats into them is no small trick. Their claws come out, grasping at anything to avoid the "scary" crate. You can train your cat to enjoy, or at least tolerate, his carrier.
If you need to get out the door and your cat has never seen your carrier before, try the following. Turn your carrier on its end so the door is on the top (unless you already have a top-load carrier). Next, hold your cat underneath his front legs, so he is more or less hanging in the air, then place your cat in the carrier back-feet first.
If your travels are in the future, take time to train. Bring out your carrier, open the side doors, and place treats just inside. If your cat won't approach the carrier, place the treats as close to the carrier as you can without making him afraid.
Repeat several times daily, slowly inching the treats inside the carrier as your cat loses his fear. Say the word "inside" when you place treats in the carrier, so he associates the carrier and the word "inside" with good things. Let him eat the treats and leave on his own. Do not close the door.
After a while, start shutting the door for a few seconds and then for longer and longer periods, so he becomes accustomed to enclosure in the carrier. Put a soft pad in the carrier to make it more hospitable. You'll soon find your cat goes into a carrier more willingly.