The nine-letter solution to crossword puzzles asking for devices increasing aircraft endurance is THERMALS. These rising columns of warm air are exploited by glider pilots and soaring birds to maintain or gain altitude, effectively extending time aloft without engine power. They are formed by uneven heating of the Earth’s surface, causing pockets of air to become less dense and rise.
Utilizing thermals is crucial for long-duration glider flights and plays a significant role in the migratory strategies of many bird species. Understanding and predicting thermal activity is essential for both recreational and competitive gliding. The study of thermals also contributes to meteorological understanding of atmospheric convection and energy transport.