It's a big day for the royal family. The royals were greeted at the abbey doors by the Dean and Chapter of Westminster, before taking their seats.
Today, Meghan chose a long-sleeved, A-line black dress by Dior (it had a boat neck very similar to her wedding gown), a Stephen Jones hat and nude high heels, continuing her preference for neutral colours, simple silhouettes and French designers.
The RAF, described as the world's first independent air force, was founded on April 1, 1918 as an armed force independent of the British Army and the Royal Navy.
The queen, 92, front and center for the RAF events. Since Kate is on maternity leave, she wasn't expected to attend the event, though Westminster Abbey confirmed she would be there when they released the order of service on their Twitter account in the early hours of Tuesday morning.