The crew rest time is a great concern; I mean I've have had to stay late in order to get the last flights out, and those pilots on those flights were supposed to turn around and do one of the first flights out of those cities. One night things were all shot to hell, bad weather led to major IROPS, we had rampers bailing out on us, and by 1 a.m., our entire ramp crew consisted of about 12 people, three rampers, six ramp leads, and the three overnight guys. We didn't get our last flight out until 4:15 in the morning, and that flight had been delayed about 5 and a half hours, due to the weather and MX on the a/c. We didn't get our ops back on track until late in the afternoon that day, because so many of the morning flights had been cancelled because of crew rest requirements, and it took that long to get everything back in order. Now with int'l flights, I think there should always be two crews on board, even on an 8 hour flight, just in case. I mean do the flight in shifts, a few hours on, a few hours off. Now with shorter flights, delays can really add up in how much time a crew is actually in the cockpit, sometimes they may fly their daily max, and on top of that sat and waited for about that long; many pilots face 12+ hour days, and may only be in the air for half of that.