It all depends on so many factors. My baby is nearly a year old and we've been on a few foreign holidays, including one that involved a transatlantic fight. The flights have actually been ok, and some babies are fairly portable. BUT and it's a major but, there can be a price to pay. Travelling around lots on our last trip seemed to dislodge our baby from sleeping through the night, and it took a week or so after getting back to get her sleeping through again. That was tough with being back at work, and we ended up being pretty tired instead of refreshed!
Sleep is such a major thing for parents (because it's HARD getting woken up a lot!), so try not to judge your pals if they doing what they need to to get that precious sleep...
I don't do anything that derails the bedtime routine, and so haven't taken our baby out in the evenings since she was younger (until I think about 6 months old she would stay asleep in the pram, so we could get away with it). We take it in turns to be out late, or get a babysitter.
By contrast, we are fairly relaxed about going out during the day, even though it can mean a later nap (or a nap in the buggy) for our baby. But not all babies will sleep in a buggy. If babies are tired and can't get to sleep, they cry... which isn't fun for anyone.
Routine seems like a drag but I cling to ours a bit because our baby has slept through from young without us having to let her cry... and although there's no way to know if that's due to her routine, I don't want to upset the applecart by messing with what works.
Also often going abroad means no childcare: your friends might like to stay local where family or trusted babysitters can give them some time off... Our next major trip will be to an all inclusive resort with a baby club... the younger me would probably scoff but there we go: we all change!