American Airlines is refreshing its buy-on-board menu in economy class, and while its onboard menu will still lag competitors, it is another sign the carrier is finally paying attention to the onboard experience, even for the people sitting in the back. American Airlines Upgrades Main Cabin Food And Snack Menu American Airlines has announced an expanded lineup of snacks and fresh food options in Main Cabin, with new buy-on-board meals and snack boxes rolling out this month. That may not sound especially exciting, but it represents an important investment in the economy class product, especially as competitors like Alaska Airlines and Untied Airlines offer excellent choices behind the curtain.…