If a recall Finland is in the EU and under the EU law no single country can work a bilateral agreement. The UK has to negotiate a new travel deal with the EU.
1- the U.K. has no individual agreement with USA or Canada . ( this agreement was signed by the EU with USA and Canada.
2- UK can not signed any bilateral agreements until it has fully exited the EU.
3- It doesn’t matter if it’s Finland or Malta the same problem will affect all the flights between the EU and the UK