谁能帮我解释一下下面这段话?麻烦请自己翻译一下~不要用机器翻译

谁能帮我解释一下下面这段话?麻烦请自己翻译一下~不要用机器翻译
Southwest is asking passengers to buy a second seat if their girth prevents the armrest from lowering. The airline is also flying slower - by 72 seconds, for example, on Houston to Los Angeles flights, which now take 3 hours 14 minutes. That saves 33 litres of fuel for each of the airline's four daily flights on the route, or 132 litres a day overall.