You choose to fly a plain, and they do not want things on the plane, if you have something illegal on you, why the fuck are you boarding a plane?
Your car can only be searched if a policeman pulls you over for a valid reason. They can not search anything locked in your car without a warrant.
anything found in your car due to an illegal search can not be used against you.
You can only be arrested for a valid reason, anything found while searching you, if the arrest was invalid, is not admissible in court.
Of course they are going to profile you. If the majority of terrorist are muslims, why would we randomly search an elderly woman, when a young muslim man saying prayers beside the terminal is a logical choice for a search.
As for your right to refuse a search, if someone is requesting permission, say no. Just like inviting an officer into your home gives them right to search it. Know your god damn rights or lose them. When I watch videos of people getting assaulted by cops they make so many mistakes. If you wish to leave, ask the cop if you are being detained, if he say no, leave. If they want to question you about a crime, say "I have nothing to say." No one has ever talked a cop out of arresting a suspect, and anything you say is hearsay, but can be used against you.
Being ignorant of your rights, is no more an excuse than being ignorant of the laws.