Imagine a ship is a Vogon vessel and you've pretty well got the idea. Ferry The easy way. Air Travel Plane Difficult. Pretending to be luggage is not a good idea. There is hardly any other way to get on board without paying.
Security is very strict at airports.
Helicopter Go to a near mountain far from the civilized world. Break your leg. Getting out of the hospital is the difficult bit. Ultralight Also frequently an ingredient of a large range of food products. The adventures of James the Birdman.