As was the case in other countries, air transportation in Japan up to the Pacific War was an expensive means of transport primarily consisting of passenger aircraft that had been remodeled from military vessels. Japan's private aviation sector really started in earnest as of 1951 with the reopening of domestic air routes. The 1960s saw the introduction of jet aircraft, and the debut of the Jumbo Jet in 1970 paved the way for large-volume, high-speed transportation. In recent years, the so-called large-scale economic aircraft have come onto the scene, while Japan has also seen the opening of the New Tokyo International Airport and Kansai International Airport. Provisions to serve these also include ground-based facilities and means of access to airports and city centers, among other developments.