Is it possible to get the Cuban tourist card (visa) on arrival at Havana Airport?

From Wikivoyage:

A tourist visa card (visa de tarjeta del turista) is necessary for travellers from most nations. This visa, which is really little more than a piece of paper on which you list your vital statistics, costs between 15-25 CUC (or 15-25 Euro), depending on where purchased. It can be purchased at the Airport in Cuba on arrival, however it should be noted that many airlines will require a valid tourist visa card before boarding flights. It is usually valid for 30 days and can be extended once for another 30 days at any immigration office in Cuba (for 25 CUC) - beyond this you would need a flight out of Cuba within the extended visa period. Canadians are the exception, getting 90 days on arrival and can apply for a 90 day extension. Your passport needs to be valid at least six months past the end of your planned return.

But that some countries don't need it:

Citizens of Antigua and Barbuda (28 days), Barbados (28 days), Benin, Bosnia and Herzegovina, CIS (except Ukraine and Uzbekistan), Dominica, Grenada (60 days), Liechtenstein (90 days), Macedonia, Malaysia (90 days), Mongolia, Montenegro (90 days), Namibia, Singapore, Slovakia, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Serbia (90 days), Turkmenistan who can stay 30 days without visa.

It's also worth noting that it's different if you're an American citizen....with more details on the same Wikivoyage link.

They handed us these cards aboard the airplane.

We went there recently and were simply given these cards on board. It was in many ways similar to filling out customs declarations for various countries, except that the form was much shorter. The flight attendants warned us to fill them out carefully as there was a fee of 60 CUC for corrections and replacements.

As stated by Timatic, the database used by airlines:

Tourist Cards (Tarjeta del Turista) must be obtained prior to arrival in Cuba. They are available at: - Cuban Embassies or Consulates; - Authorized airlines; - Travel agencies.

Condor (from Frankfurt) and Edelweiss (from Zurich) are two airlines I know sell it, while most airlines flying from Canada distribute it for free on the aircraft.

It is possible to buy it in Cuba but it will cost more than in your country - if I remember correctly ~75 EUR. As is it mentioned before, some airlines won't let you depart if you haven't card.