A big distinction between the life our speaker leads and the one he imagines when "Reading Moby-Dick at 30,000 Feet" seems to be a connection to the natural world. In his passive position reclining on an airplane, our speaker's about as far from the world as he can get. Out on the open sea, the crew of a whaling boat feels the sea spray, the deck rolling on the waves beneath them.
The sense of adventure our speaker desires requires facing elements of the natural world that are not controlled—the whale and the ocean. The relationship is at once one of enemies, fighting against wind and waves to stay afloat, and trying to kill the whale, and also a symbiotic relationship, since you can't be a whaler without an ocean and whales.
Riding in an airplane is just like a modern-day version of being on a whaling boat. They're both about conquering nature to serve human needs.