My understanding is that TP has a comprehensive codeshare in place with PS.

I assume that Ukraine is not burdened by costs and restrictive labour agreements on the same scale as TAP's, so a non-operating codeshare on this essentially low-yield route is clearly the way to go. Increasing capacity on KBP with high-cost TP-operated seats would dilute any benefits the two airlines derive from their cooperation.

Bucharest is a puzzle. I'm a generous sort, so I'll assume the planners in Lisbon know a lot more about the demand side than I do. Certainly the overnight A319 schedule improves the wider utilisation of the fleet, and the arrival time into LIS gives good connections, but still....

The press release concerning BUH and Romania seemed a tad defensive. It failed only to promote the impact of the two nations' common language roots, and Sesimbra's twinning with the Romanian town of Siret