Bill Clinton is the husband of the woman that Lynch is investigating and it was most definately against protocol for the two of them to meet. Hopefully nothing illegal occurred during that meeting, but both from a political standpoint and a legal standpoint it was inappropriate for the two of them to meet.
Attorney General Lynch's meeting with Bill Clinton on her private jet was incredibly inappropriate, given the fact that her Justice system is in charge of his wife's investigation for her misuse of personal email and leaking of confidential government information. Bill himself is also under investigation by her justice system.
Yes, Loretta Lynch's meeting with Bill Clinton was inappropriate. They could have met any other time to have a social meeting, which is what the attorney general claimed it was. Because of this meeting, it is possible that Loretta Lynch may be unsuited to continue the investigation into Hillary Clinton's email scandals.
Attorney General Loretta Lynch's private meeting with Bill Clinton was inappropriate. Lynch, who overseas the FBI at the Justice Department, is supposed to provide an unbiased decision when it comes to the FBI's recommendation as to indicting Hillary Clinton. If Lynch cannot be trusted because of her close ties to Bill Clinton, then the investigation won't be taken seriously.