You CAN bring nail polish on a plane.
You can bring nail polish on your next flight as long as you follow certain restrictions as set forth by Transportation Security Administration (TSA).
TSA Liquid Restrictions
Size Matters: Liquids such as nail polish must be in individual containers and cannot be more than 3.4 oz or 100 ml each. Most nail polishes are smaller than 1 fluid oz. Anything larger than 3.4 oz must be transported in the luggage to be checked and cannot accompany you on the plane.
Approved Zip-top Bag: You nail polish must be packed separately from your clothing in a clear, plastic, zip-top bag. It can be no larger than 8"x8". The clear bag that contains your liquid items cannot be jam-packed. The bag must zip close comfortably.
Airport Security for Nail Polish
Be aware that if you do opt to carry on items such as nail polish and other liquids, it may take you longer to clear security. You must submit your clear plastic bag of liquids separately from your other carry-on baggage at the inspection point. You may also be subject to a secondary inspection prior to boarding.