(Reuters) -Southwest Airlines said on Tuesday it had ordered 34 new Boeing Co 737 MAX 7 aircraft to receive in 2022, as the U.S. airline prepares for a vaccine-driven recovery in travel demand. The move brings the carrier"s total orders for the MAX 7 to 234. (bit.ly/3pvTNgF) Shares of Southwest were up 1.1% at $58.92 in premarket trading, while Boeing rose 1.4%. Bookings for U.S. airlines are expected to rebound this year on the back of speedy COVID-19 vaccinations and easing restrictions after the pandemic caused one of the industry’s worst downturns in 2020. Southwest said it expected revenue to continue to improve in June, driven mainly by leisure travel. It also tightened its second-quarter average core cash burn forecast to between $1 million and $2 million per day, compared with the previous range of $1 million to $3 million per day. But the company said that weak business travel, which has lagged a recovery in leisure demand, would continue to impact its fares in the second quarter. Reuters last month reported that Boeing had drawn up preliminary plans for a fresh sprint in 737 MAX output to as many as 42 jets a month in fall 2022, in a bid to extend its recovery from overlapping safety and COVID-19 crises. Reporting by Sanjana Shivdas in Bengaluru; Editing by Aditya Soni Our Standards: The Thomson Reuters Trust Principles.