WHen I have flown Airlink (and will be flying them again in November '23), tickets have always been purchased through travel agent because of inability to combine with a United ticket purchased through united.com on a business class fare. Too complex to discuss now. However, it would have been possible to purchase a through ticket in coach. Travel agent was able to purchase two tickets but combine on one UA PNR for purposes of interlining baggage. I note that a ticket JNB-BBK and return MUB-JNB was $500 for return ticket. Of this $250 was ticket and $250 taxes and fees. And I would gladly pay it for the peace of mind that there is a far greater chance of Airlink staying afloat than SAA. And if SAA goes so does the money for that ticket you bought. So for your Airlink ticket, buy through a travel agent who can book it through their Amadeus or Apollo or whatever system they use.