Containers
Travelers routinely use plastic garment bags when they need to fly with formal clothes. To reduce wrinkles, your bag should be as tall and wide as possible to contain the garments. You also have the option of packing your formal attire into a sturdy, water-resistant shipping box. As long as it is large enough and not packed tight with other items, a suitcase can also work for transporting your formal wear.
Packing Gowns
Hanging a formal gown upright during a flight is the best way to prevent wrinkles. Because this may not always be possible, you might need to take other steps. Wrapping the garment in acid-free tissue paper and placing layers of tissue paper in between folds can reduce the potential for wrinkling during flights, because the tissue makes the fabric less likely to bunch and crease.
Tuxedos
Hanging a tuxedo in a full-length garment bag or box helps prevent wrinkling, but if your airline cannot or will not accommodate one, neatly fold the tux into a suitcase. Place the jacket, shirt and pants into separate plastic bags, such as those supplied by dry cleaners, and fold them over as few times as possible to fit into your case to avoid excessive wrinkling. When the jacket is turned inside out and folded gently, the appearance of wrinkles may be less apparent. Unpack, unfold and hang the tuxedo as soon as possible upon arrival.
Flight Plans
Some people have gone to the extreme of buying a separate seat on the plane to transport their formal attire. If your travel budget forbids that, consider inquiring with the airline ahead of time whether its possible to make arrangements for the garments to be hung or stored in a closet near the front of the cabin. Checking formal wear in a suitcase does not guarantee it will arrive at your destination with you. You can also reduce the bulk of hangers, irons and steamers you might need by calling ahead to make sure they're available at your destination. The longer a formal garment stays folded before, during and after a flight, the more likely it will retain wrinkles.