Einstein's theory was that everything about the laws of the universe and nature was relative. What you observe about something depends greatly upon your frame of reference at the time. That's why I can stand here in this concord cabin and drop my pen in comfort. In here I'm not traveling 1,400mph, am I? Everything works like that. Conditioned by its frame of reference. All the electronics in all the instruments in this cockpit obey the exact same laws they would if the plane were standing still. Because in this frame, like me they are not traveling at Mach two. And all the laws of nature behave the same way. This beam of light is going out in all directions at 186,000 miles per second. Being on the concord makes no difference to it's speed going forward, backwards sideways.
James Burke (science historian)