The Dutch airline KLM made its first flight in 1920, and is the oldest continuously operating airline in the world. Established by aviator Albert Plesman,[11] it was immediately awarded a "Royal" predicate from Queen Wilhelmina.[12] Its first flight was from Croydon Airport, London to Amsterdam, using a leased Aircraft Transport and Travel DH-16, and carrying two British journalists and a number of newspapers. In 1921, KLM started scheduled services.

Hydra is great but it does take a bit of time and effort to get to from the Cyclades. You’ll need to ferry to Athens, then might have to overnight there, then ferry to Hydra. Whereas Naxos, Paros, Milos, Folegandros, etc. would all be one direct ferry from Santorini or Mykonos. If you do go to Hydra then Leto Hotel is a great choice close to the port and shops and restaurants.
That all sounds good though I would recommend Naxos over Mykonos in March as there’s more to see and do there when not beach weather. And if you do decide to do Mykonos be sure there’s a ferry from Mykonos to Santorini for your dates. And same for Santorini to Crete. There should be ferry service but the route starts different times every year so you do want to be certain.

Among the first countries to have regular airlines in Latin America and the Caribbean were Bolivia with Lloyd Aéreo Boliviano,[57] Cuba with Cubana de Aviación, Colombia with Avianca (the first airline established in the Americas), Argentina with Aerolineas Argentinas, Chile with LAN Chile (today LATAM Airlines), Brazil with Varig, Dominican Republic with Dominicana de Aviación, Mexico with Mexicana de Aviación, Trinidad and Tobago with BWIA West Indies Airways (today Caribbean Airlines), Venezuela with Aeropostal, Puerto Rico with Puertorriquena; and TACA based in El Salvador and representing several airlines of Central America (Costa Rica, Guatemala, Honduras and Nicaragua). All the previous airlines started regular operations well before World War II. Puerto Rican commercial airlines such as Prinair, Oceanair, Fina Air and Vieques Air Link came much after the second world war, as did several others from other countries like Mexico's Interjet and Volaris, Venezuela's Aserca Airlines and others.
The only ferry from Kusadasi to Greece goes to the Greek island of Samos. It’s a great island and certainly worth a few days. From Samos, there are usually direct ferries to Mykonos and Syros. These are very different islands that have a very different vibe – but both appealing in their own way. From Mykonos there will be direct flights to Western Europe (most likely Rome, Paris, Amsterdam, and London) though not every flight flies every day so requires some planning. Santorini would be another ferry ride from Mykonos. And Crete farther still. So you wouldn’t have time to get to either island.
Airlines often have a strong seasonality, with traffic low in Winter and peaking in Summer. In Europe the most extreme market are the Greek islands with July/August having more than ten times the winter traffic, as Jet2 is the most seasonal among low-cost carriers with July having seven times the January traffic, whereas legacy carriers are much less with only 85/115% variability.[73] 

Although Philippine Airlines (PAL) was officially founded on February 26, 1941, its license to operate as an airliner was derived from merged Philippine Aerial Taxi Company (PATCO) established by mining magnate Emmanuel N. Bachrach on December 3, 1930, making it Asia's oldest scheduled carrier still in operation.[52] Commercial air service commenced three weeks later from Manila to Baguio, making it Asia's first airline route. Bachrach's death in 1937 paved the way for its eventual merger with Philippine Airlines in March 1941 and made it Asia's oldest airline. It is also the oldest airline in Asia still operating under its current name.[53] Bachrach's majority share in PATCO was bought by beer magnate Andres R. Soriano in 1939 upon the advice of General Douglas MacArthur and later merged with newly formed Philippine Airlines with PAL as the surviving entity. Soriano has controlling interest in both airlines before the merger. PAL restarted service on March 15, 1941, with a single Beech Model 18 NPC-54 aircraft, which started its daily services between Manila (from Nielson Field) and Baguio, later to expand with larger aircraft such as the DC-3 and Vickers Viscount.
Airlines have substantial fixed and operating costs to establish and maintain air services: labor, fuel, airplanes, engines, spares and parts, IT services and networks, airport equipment, airport handling services, booking commissions, advertising, catering, training, aviation insurance and other costs. Thus all but a small percentage of the income from ticket sales is paid out to a wide variety of external providers or internal cost centers.