[...]
Airbus should include color smoke generators off each wingtip to colorize
the vortices and give VFR aircraft something visually to avoid.

Different color smoke from each wingtip would be very pretty.

But imagine the mass of smoke agent that would have to be dispensed in
order for it to be visible 5-10 miles behind the jet. There would be
a terrific amount of dilution through the air, moving at that kind of
speed.

- FChE