Federal law has not made marijuana legal, and TSA follows federal law, so the short answer is- no, it is not legal to fly commercially with marijuana. Some states have legalized specific amounts of marijuana. Some states have changed their marijuana possession criminal laws.
In Maryland, Marijuana is legal for recreational use starting July 2023. However, possession of more than 1.5 ounces of cannabis is a misdemeanor punishable by law. Medical marijuana is also legal in Maryland, unlike Federal Law. Medical marijuana patients in Maryland can purchase their medicine from one of the state-licensed dispensaries.
Travelers are justifiably concerned about what will actually happen if they are caught with marijuana at airports. The short answer to that is, it depends on what state you are in. TSA is not focusing on finding marijuana when travelers go through checkpoints. TSA is not actively searching for marijuana, but if they find marijuana, they are supposed to contact local law enforcement. TSA checkpoints follow federal law, so it is still illegal to travel with marijuana. Some airports provide boxes that travelers can throw out their weed in prior to going through TSA.
TSA does permit marijuana products with no more than .3% THC, and those products can be in a carry on or in checked luggage. In general, the best advice to travelers going into BWI is to not travel with over 10 grams of marijuana because they could be criminally charged.