If AG Lynch were a district attorney in DC, she would have been guilty of violating the legal ethics of the DC Bar for this meeting on the tarmac
Rules of Professional Conduct: Rule 8.4--Misconduct
It is professional misconduct for a lawyer to:
(d) Engage in conduct that seriously interferes with the administration of justice;
(e) State or imply an ability to influence improperly a government agency or official;