The reservations for two airplane tickets to Paris are made under Jennifer's name. When at NORAD McKittrick tells David he's got reservations to Paris and demands to know who he's working with.
I can't believe I've never noticed this! I've seen this movie a dozen times or more and now that you mention it, he DID make the reservation in Jennifer's name. In fact, and I'll have to watch again for this, I'm not sure he ever enters his own name as the one accompanying her. I think he just indicates that there will be two passengers. Remember, this was back in the day before you had to show ID and let someone look up your kazoo before boarding a plane. Outstanding.