Thomas Cook Airlines is still very much a charter airline predominantly flying passengers affiliated with Thomas Cook Holidays and is no way a full low cost airline in the same way as EasyJet or Ryanair 'giving two examples' regardless of their recent expansion of scheduled long haul transatlantic flying from Manchester there still very much a holiday airline in a similar way to TUI (Thomson) offering a full package holiday like a lot of tour companies did in the past. Thomas Cook Holidays and TUI(Thomson) are the only true remaining package holiday companies left in the United Kingdom.
In comparison Jet2 holidays are based around their low cost airline Jet2 where as Thomas Cook Airways have always been based around Thomas Cook Holidays even if they do hire third party airlines, this format hasn't changed regardless of scheduled long haul flying.
What came first the airline or the holiday company? :-)