MINNEAPOLIS (WCCO) — A war of words continues between Delta Air Lines and labor unions trying to get certain airline workers to unionize.

The latest round started with flyers showing images of a football, baseball or video game controller, with messages like “what you could do with $700 you don’t spend on union dues.”

In a statement to WCCO, Delta says they have shared many communications that make it clear that deciding whether or not to unionize should not be taken lightly.

Delta says, “Our employees have the best total compensation in the industry … They want and deserve the facts and we respect our employees’ right to decide if a union is right for them.”

Currently, only Delta’s pilot staff are unionized. The International Association of Machinists and Aerospace Workers is trying to change that.

That union is a member of the AFL-CIO, which tweeted and deleted a meme Thursday night showing a guillotine and referencing Delta’s CEO. A union representative said they realized it was in poor taste.