We have long advocated the benefits of a (BOV) American Express card, which enables you to benefit from the excellent Membership Rewards points scheme (infinitely preferable to, for example, BOV reward points).
Among many other options, it is important to remember that you can swap Membership Rewards points for Avios, which you can then spend on BA flights.
One major disadvantage of American Express cards and the Air Malta website is that while you can use it to pay for flights to Malta, you cannot use it to pay for flights from Malta (while it seemingly should be, the Amex payment option is not presented). This is a pain, because it means large flight spends will not earn Membership Rewards points.
There is a very simple workaround to this.
Select your flight via the websites as normal, but rather than actually paying for it online, simply book it via the (in my experience, very helpful) Air Malta call centre on 21662211.