Quick answer - you can't. You can't move objects around. If you want to have a carrier in a particualr location you have to put one there. A carrier in a spot on the ocean is a scenery, so you will have to learn a bit about scenery design.

However - all is not lost. If you download my MakeScene package which is a cut-down version of the FS2004 SDK with an easy tute, it will let you easily place a default carrier wherever you want. Make sure though that you leave the scale at 1.00 (which is actually a wee bit small) otherwise the 'hard surface' falls below the deck level.