I would recommend Naxos over Mykonos and with 12 days you could easily add Paros too. With Santorini, Paros, and Naxos you’ll get a good mix of different delights and some ferry island hopping too which is fun in itself. 1.5 days in Athens is perfect for most – 1 day for the Plaka, Parthenon, Acropolis Museum area; and a half-day to visit the Archaeological Museum which is a short drive or walk from the Plaka but hard to fit in one day along with the other sights.
Glad to see you mentioned the Cook Islands – my husband and I went to Rarotonga for a week in 2008 and fell in love with it – can’t wait to someday bring our kids back there – they would love it, too! Very few people have actually heard of the Cooks, or know where they are, and while I like the “secrecy” of it, I wish more people would visit! Currently there are only 1-2 flights/week from the US – makes planning trips there a bit tougher!We only took a day trip to Aitutaki because of time, but it was probably the most beautiful place I’ve ever been. Glad to see you agree!
Despite continuing efficiency improvements from the major aircraft manufacturers, the expanding demand for global air travel has resulted in growing greenhouse gas (GHG) emissions. Currently, the aviation sector, including US domestic and global international travel, make approximately 1.6 percent of global anthropogenic GHG emissions per annum. North America accounts for nearly 40 percent of the world's GHG emissions from aviation fuel use.
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.