Help wanted for track (Spore)

Hello.
My son is stuck in the track. He is in the phase where all based cities are similar to himself, and he has built cities, vehicles and ships, and he has conquered the 4 cities on the same land, but how can he move vehicles and troops across the ocean ? He has tried to move "cars" (they look strange out!) on board the ships, but it can not. He can not find a way to establish a commercial relationship with a friendly city on the other side of the ocean. Both he and I have read in the help that is to find in the game, but none of us can find something to cross the ocean.
How is it done?

He must enter and buy aircraft. He chooses only a design for it in there where we can change the design of its vehicles and boats, and then they bought like.

Do as it is seen.

You can easily capture all the power, without using planes, I have achieved. It gives Fear of flying badge, if you collect them.

Yes he can build some aircraft, or both, if he uses military, he can attack the remaining cities.

What I usually do (by war) is to build an entire fleet, and then attacking the city which is closest to the coast. Is there demanded from coast to the city, as tonnes of barley a war plane.

Remember that for aircraft it is important that they have much health, and perhaps not so much four power again.

Another option if he is a military user, is to buy it there missiles which can conquer all the cities at once. Does it cost around 18k and says something with ICBM.

Something very different is that my Spore BAN is over now.

Yes. Capture a town with airplane, and barley as cars with the new city.

Remember that you can only build ships in coastal cities. If you can not make any more vehicles, it is because you've reached the maximum limit. So you can erase some of the cars again by looking at their icons in page and then press the little red cross in the corner of the icon. There after, you can create new boats, planes, etc.