New Zealand had 24 days with no new cases, and most of that time with no active cases. After that, we opened the border a bit to allow New Zealand citizens and permanent residents to come back, and have had 16 new cases from that (5 from Australia, 1 from USA, 10 from India). Those cases arrived on 6 different flights.
I'm fairly comfortable with those numbers; although I don't know what the percentage is among returnees (I understand the flights weren't full, but don't have numbers of actual passengers & crew.)
There has been some outcry about quarantine, ie housing persons from different flights in the same hotel, questions surrounding availability of quarantine hotels to meet the demand for returnees, releasing some persons on compassionate grounds without a final test, the necessity of not requiring a full 14-day stand-down quarantine regimen for flight crews, etc. So far there is no evidence of community transmission.