As a youth, a British Airways 737 was a regular sight.  The 200 series got a ton of use by BA and, in later years, the 400 series did a lot of work at Gatwick.  The A320 family gradually displaced them all.  However, Comair in South Africa flies in BA colors.  They even had 727s in BA colors in days gone by.  IAG, the parent of BA, signed a letter of intent with Boeing for 200 737 Max aircraft but this has not been turned into a firm order that I know of.  However, Comair did order the Max and one of their aircraft was on test recently.  I am not sure if it is still going to Comair or has been reallocated to another customer but it is still in British Airways markings – for now.