I think when Spooky refers to 'airlines' that also encompasses the charter side, be it airliners or charter operators of business jets. Operators of purely corporate nature do not have to adhere to ETOPS regulations, although that does not stop them from adopting 'best practise' operations.
If just talking about US based operators then ETOPS is more restrictive for the 'airlines', i.e. 121 operators as the starting point is the 60 minutes, whereas for the the 135 operators its 180 minutes.
Buzzz