One of the main causes of suits becoming crumpled in transit is because they are overpacked, with too many items in the suitcase. Because there are often strict limits on how heavy our bags can be or how many bags we can take when we fly, we naturally try to get as much in as possible into to get value for money.
This isn't really the right approach when trying to carry something as sensitive as a fine suit.
In days gone by, travellers with suits would use a garment bag to carry their suits onto the plane separately. Nowadays, a garment bag needs to be checked in separately as extra luggage, usually incurring an extra fee. Carry-on luggage, while compact and convenient for light travel, can be too small to transport a suit with enough room to avoid wrinkles.
If you absolutely have to travel with just hand luggage, invest in a small travel iron or steamer. This could be a worthwhile outlay, as you can then fix any wrinkles you get from having to pack your suit into such a small suitcase when you get to your accommodation.
Hotels often have dry cleaning and ironing services, especially if they're a luxury or business hotel brand. If all else fails, hanging your suit up in a steamy hot bathroom when you arrive at your destination should still do the trick.