In Level one is it just best to invest in one plane and one ship so that 4 containers are unloaded?

Once you have purchased an asset ~ plane, ship, train or truck ~ you own it and should re-use it as often as necessary to extract the most benefit from your purchase.

On the face of it buying more than one ship and one plane will provide enough capacity to deliver four containers and meet the four orders BUT a player could:

• Use the same ship twice and deliver 6 containers….just in case some containers are lost/go missing, are stolen etc !!!
• Use one plane 4 times (avoiding excessive investment in planes)… or 2 planes twice

In their first ever game, many players are naturally cautious and just buy either one plane or one ship. Much depends, however, on the example the first player sets… The key advantage of investing in two assets, of course, is being able to use two dice. That’s why most players playing for a second or third time choose to buy either one ship & one plane, two ships or, occasionally, 2 planes. We prefer players to learn by experience.