Answer is no if you do not have proof of residence
I'm flying into Santo Domingo with Condor. My plan is to go to Central America from there, but I don't have a ticket yet. Can I fly into the Dominican Republic on a one way ticket?
If you can not show a proof of residence (domicile in passport, foreign residence identity card) the airline almost certainly will refuse boarding.
You then have the option to buy a return ticket before boarding (which can be expensive).
Final decision has the purser of the shift.
I know this because once an Air Berlin employee wanted to refuse check in with my one way ticket without residence ID.
Luckily, remembered that I at that time had my dominican residence written in my passport andthis was accepted.
Think the reason airlines are picky about residence is that some regulation requires them to return passengers at their cost in case they do not have required documents to enter (which might include a return ticket).
Alexander