What we know is this. That same plane flew out of Belize last Thursday for Aruba, and had filed a flight plan to return on Sunday, but did not; it simply appeared this morning. Now, that might sound straightforward enough, but it's illegal - and very suspicious. Every single plane that lands legally in Belize - big or small - has to first file a flight plan with Civil Aviation and then land at the Phillip Goldson International airport to clear customs and Immigration. Of course, planes with illicit cargo, or illicit business do no such thing - but those ones usually land on improvised airstrips deep in the bush, not in Belize City - the country's largest population center. So, did the plane have an illegal cargo or an illegal passenger? Police don't have any clues at this time - and no one to ask since the pilot parked the plane and rolled out. We do now that the anti-drug unit is in charge of the case. Because of where the plane landed, Police suspect that the cargo, if illicit, was currency - cash money which can easily be fed into the system. The plane was not outfitted for long distance flying - which drug planes usually have. If and when the owners do appear - they will be criminally charged for an unauthorized landing.