** Shares of Southwest Airlines LUV.N rise 4.9% to $53.61

** UBS upgrades the airline's rating to "Buy" from "Neutral"; raises PT to $73 from $51

** Brokerage expects LUV's new cabin strategy such as Extra Legroom (ELR) to generate far greater earnings than expected, with revenues from assigned seating, and checked bag fees severely underappreciated

** UBS also sees a supportive macro environment for co and estimates LUV lost around $700 mln in revenue post Liberation Day weakness, a hit it expects the airline to at least partly recover

** The new PT represents a 42.8% upside to LUV's last close

** Including session's move, LUV up 29.5% YTD