Excellent choice of islands, though getting between them presents one or two challenges (they are not as conveniently connected like the Cycladic or Dodecanese islands so island hopping is not as popular in this island group). All three islands are served by airports with year-round connections to Athens and in the Summer with international charter flights from Europe. Let’s take the pros and cons of each island.
Since airline reservation requests are often made by city-pair (such as "show me flights from Chicago to Düsseldorf"), an airline that can codeshare with another airline for a variety of routes might be able to be listed as indeed offering a Chicago–Düsseldorf flight. The passenger is advised however, that airline no. 1 operates the flight from say Chicago to Amsterdam, and airline no. 2 operates the continuing flight (on a different airplane, sometimes from another terminal) to Düsseldorf. Thus the primary rationale for code sharing is to expand one's service offerings in city-pair terms to increase sales.