and activities they fund, so it's appropriate and common for them to investigate complaints of discrimination brought to them.
The allegation is that the airports discriminated against Chick-Fil-A based on their religious beliefs in violation of statutes and rules. According to news reports, the San Antonio and Buffalo city councils excluded Chick-Fil-A from the list of airport vendors because of a history of anti-LGBTQ activity, including donations to anti-gay rights organizations. The question for DOT will be whether Chick-Fil-A's actions constitute discrimination within the legal definition and, if so, whether that is sufficient to support exclusion from participation or whether the donations are a protected act of religious expression.
This may be a difficult move for the cities to defend since donations to anti-LBGTQ organizations, while offensive to many of us, isn't the same thing as, for example, a policy of refusing to hire gay or trans persons or to serve minority customers. If there's no evidence of discrimination in the conduct of their business and customer service but the exclusion was based on where the owners choose to spend their profit dollars, they may be able to prevail.
That said, while most of DOT's political leadership aren't known to be particularly sensitive to minority rights (to put it mildly) the FAA's Office of Civil Rights is run by some outstanding career staff who really know their stuff and whom I trust to conduct a fair investigation. The final decision will be made by DOT's political leadership BUT, these investigations can take a long time (many months to years) and if the department finds Chick-Fil-A was discriminated against, there's another long process before DOT can actually take any adverse action. So it's possible the political leadership will have changed well before this is resolved.