 Boeing and United Airlines are to make a historic announcement on Tuesday.Using the word historic certainly catches your attention.Boeing shares closed 179. It is currently trading in after-hours trading at 178.64. Meanwhile United Airlines closed at 42.80 and is currently trading at 42.85.Boeing shares are up from a September 30 low of 120.99. Thats a gain of 48. Meanwhile United Airlines is up 35 from its October 3 low.The post Covid travel demand is... 