Chuuk is served by United Airlines, which connects the island to Honolulu and Guam on its "island hopper" route across Micronesia. The route stops at several FSM islands in sequence, so you can combine Chuuk with visits to Pohnpei, Kosrae, or the Marshall Islands.
The airport is on Weno (Moen) island, the main administrative centre of the lagoon. Boats connect Weno to the other inhabited islands within the lagoon; liveaboard dive vessels are the best way to reach the outer reef.