Air Sol is an airline in Grand Theft Auto IV. An online article on Liberty Tree's website mentions that an Air Sol flight has 212 passengers on board, 212 being a reference to the area code in New York City. On the Rockstar Games Social Club website, an Air Sol plane ticket can be found for Niko Bellic to go from Liberty City to San Andreas.
The name Air Sol might have been chosen because, when spoken quickly, it sounds like "arsehole", which fits with the suggestive slogans and the logo that resembles an anus. Several of their advertisements feature innuendos of anal sex. Sol also means "sun" in Spanish, which explains it's slogan, as well as an abbreviation of "Shit outta Luck".
Weazel News reports on the radio that Air Sol is struggling to cut costs and plans to install paid toilets in their planes, upsetting many passengers. The company might have gone bankrupt or may have terminated the Liberty City-Los Santos route in 2013 as, unlike FlyUS and Adios Airlines (Other two airlines featured in GTA IV that return in V), none of its airplanes are found in Los Santos International Airport, though they most likely operated large aircraft such as the Jet, as seen in the advertisement.