Youre departing on an IFR trip in a well-equipped aircraft with two passengers aboard. When you call for your clearance, ATC cannot immediately find your flight plan-you get the oft-dreaded clearance on request response. After completing all your pre-taxi checklists and entering what you expect will be your route into the GPS, youre still sitting on the ramp with the engines turning, waiting. Eventually clearance delivery returns and says they cannot find your flight plan. Take a moment, and look at the pop-up pop quiz questions in the sidebar on the opposite page. What is your most likely response if you actually found yourself in this same scenario, given the information you have so far?Lets add some additional details to this scenario. For one, the airport youre trying to depart is a busy, tower-controlled facility in Class C airspace, and under an inner ring of a very busy Class B area. To get to your destination, youll head southwest, away from the Class B airport. But youre still sitting on the ramp, with the engine running, waiting on ATC to get its act together. Does this change your response to the quiz? But wait, theres more. The weather is marginal VFR, thanks mainly to low ceilings (1000 to 3000 feet agl). Visibility is greater than five sm. Take the pop quiz again. Has your answer changed? Oh, did I mention that this is at night? Does that change your answer again?These kind of questions are standard fare for instrument pilots, and many conducting VFR-only operations in or near certain airspace. And while missing flight plans arent the norm, their not at all unusual, either.