Sacramento International Airport could end up in court over advertising you're not seeing.

It's a billboard, or lack of the same, that has the ACLU upset with Sacramento airport officials.  

The billboard is paid for by the health nonprofit California Endowment and promotes health coverage for undocumented people living in California.  

However, airport officials say it violates their policy forbidding ads of a political nature, so the Sacramento Bee reports they've put a sign which reads, #Health4All.

An ACLU lawyer reportedly says refusal to put up the contested billboard amounts to a violation of California Endowment's free speech rights.  

Airport officials are offering no further comments while this issue plays out.