Originally Posted by Jenbel
However, a 747 with one engine lost can continue onto its destination safely (depending on cause of loss - if it's one of the events where engine loss is independent of having already lost an engine ) - so it's statistically more likely that you'll have to divert in a 777 if you lose an engine, since if they lose an engine, unless they are close to home, they're looking for someplace to land for a diversion to get the problem fixed.
The heavily second-guessed BA flight from LAX-LHR excepted, I can't think of many 747 flights with passengers on board that attempted to continue to a final destination following a single engine failure. And even in that example, the flight was diverted albeit to an airport in the same country as the intended destination airport.
More fundamentally, the statistical likelihood of an engine failure causing a delay-inducing diversion on any modern jet is so rare that it probably shouldn't even factor into any equation from a delay standpoint, especially when considering the infinitely greater chances of being delayed or even diverted for other aggregate reasons such as weather, security, other mechanical problems, etc.