We're only just in February and it's already apparent that the increase in visitor numbers is putting pressure on the Aerobus service between the airport and Funchal/Praia Formosa.
It's becoming increasingly common to find a huge queue/scrum at the airport bus stop even half and hour before the bus is due to arrive - which means the buses take a long time to board (you can't buy a ticket in advance) and you may not get a seat - or even get on board at all.
There have also been times when there have been no taxis available (at least to summon online).
Heading towards the airport, the number of passengers boarding, particularly in the centre of Funchal means that buses are running at close to their maximum journey times.
There are additional SAM local buses that run into Funchal roughly hourly (on a weekday) from a different stop at the airport - it's around 50m further along in the direction of traffic beyond the Aerobus stop outside arrival - but they don't have the capacity to take luggage and take rather longer than the Aerobus. If you're travelling light, they may be a useful backup. There's a timetable at the stop.
If you're planning to travel by bus, make sure you allow sufficient time for your journey. If you're travelling in a group, it might make sense to pre-book a transfer.