The world's largest airlines can be defined in several ways. American Airlines Group is the largest by its fleet size, revenue, profit, passengers carried and revenue passenger mile. Delta Air Lines is the largest by assets value and market capitalization. Lufthansa Group is the largest by number of employees, FedEx Express by freight tonne-kilometers, Ryanair by number of international passengers carried and Turkish Airlines by number of countries served.
You’d have to check the schedule for your specific dates but I think Santorini then Milos then Paros then Naxos and Athens would probably be the best order. 3 days in each sounds great. Or a small tweak: 2 days in Milos and then 4 days in Santorini (splitting time between 2 of the 4 caldera towns) or even 4 days in Paros (splitting time between Naousa and Parikia).
Blaca Hermitage in the south of the island is a must-visit, as well as Vidova Gora Mountain, which is the highest peak on the island, offering you stunning views across the Adriatic and to neighboring islands on a clear day. Brač is also where you’ll find the famous Zlatni Rat Beach, one of the absolute best Croatia beaches (and even in all of Europe) and a wonderful place to spend a day. This all makes Brač one of the best islands near Split, a perfect day trip from Croatia’s second-largest city.
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 St. John is part of the U.S. Virgin Islands, U.S. citizens can visit without a passport. There are quite a few bargains on both St. Thomas and St. John right now, so it’s a good choice for travelers on a budget. Snorkelers should not miss visiting Trunk Bay, one of the best snorkeling spots in all of the Caribbean for seeing amazing marine life.