Introduced in Advance Wars: Days of Ruin, the Seaplanes are an Air Unit that cannot be built at an Airport. Instead, Seaplanes are built on the deck of a Carrier, but can be repaired and supplied at an Airport or Temporary Airport once deployed.
Only one Seaplane can be built per Carrier per turn, and ordering the Carrier to produce Seapalnes ends its turn. Seaplanes cost 15,000G to produce.
Carriers are limited to building a maximum of four Seaplanes total, but can use their Missiles to fire on any type of unit.
Keep your Seaplanes close to a Carrier, Airport or Temporary Airport as they go through fuel quickly.
Use your own Cruiser, Seaplanes, Fighters, Anti-Air and Missiles to protect against enemy Seaplane attacks. These units can shoot any unit type, so defending against them will be necessary in Naval battles.