Suggestions:

1) Print out a copy of your statement showing the charge, and (if available) the last-4 of the virtual card #. Bring the actual card associated with the account -- the last-4 of which should be shown on the statement.

2) Use online check-in, or even better, the app where you can scan in your passport. Even though it's been years-and-years since I've had any airline (even one of the regional Asian ones) insist on seeing the CC, I've _never_ seen or heard of this happening for OLCI. (I could be wrong, and am sure someone will chime-in if I am.)

3) Evaluate how you're purchasing tickets... While this was common behavior years ago for Delta and a lot of Int'l (especially Asian) airlines, this was never common behavior for most US carriers. When you got "flagged" to present a cc, it was usually because something about the transaction was unusual. Purchasing a ticket under a name different than the cc with a billing address other than the O&D locale of the ticket, and a soft-fail on the AVS verification for address or zipcode... For you to have that flag added to your ticket in 2017, chances are you're doing something "weird", but maybe not. *shrug*