Now, I can see the advantages of developing airplanes. Overall, they are going to be faster then a Leviathan. However, I see the cultural
impact of the Leviathans perhaps slowing down airplane development. The Wright Brothers did still fly, right?
Advantages that could be seen for airplanes in a military role right now: Less resource intensive to build, faster.
Disadvantages to Leviathans: Cannot engage leviathans, have short ranges from a fixed point of supply.
Likely uses for airplanes at this point in the Leviathans Setting: Scouting missions around border regions, Courier
Now, eventually? We might see something like WW2, where Carriers are important because the planes can carry stuff
that can hurt a Leviathan...but, that is a big, big "might." Nothing can guarantee that the Navy will make that leap to experiment.
However, developing parachutes in the Leviathans setting? That could totally change things. RL, we cannot have that many people
fit in a plane to drop off. But, imagine if, instead of the Marines becoming known for Amphibious Assaults, they became known for
Airborne Assaults off of Leviathans...
One thing is that Leviathans might, actually, have parachutes developed earlier, due to a desire to try and find ways to save the lives
of crew on a ship that is going down. The military DOES care about its sailors in this time frame, right?