Thanks for the clarification, bluemi.
So by adding some amount of text about destination 2 to the main page I'm a bit afraid the search engine positions for destination 1 will suffer.
To play devil's advocate a little, how will customers know about the new destination if it isn't mentioned on the main page in some capacity? In general, it seems like the approach is likely to hamper the potential performance of the new destination.
Your current structure seems to be like this (assuming you added an extra destination):
travel.tld (destination 1)
---destination2.travel.tld
---destination3.travel.tld
But assuming that all destinations would eventually have equal weight, you'd be likely to be aiming for this:
travel.tld
---travel.tld/destination1
---travel.tld/destination2
---travel.tld/destination3
That said, you may well be right to be cautious, as EditorialGuy suggests. You would likely have to accept that, at some point you would need a longer-term solution, but perhaps the risk might be too high at the moment?