I want to start off with the statement that the analysis below is really not specific to AR21. It applies to all Amazing Races.
A multi-part hypothesis that interests me:
1. That since LAX has been the departure to overseas airport for 89% of AR12 to AR20, LAX will be the departure airport for AR21.
2. That the destination will be either in eastern Australasia or in Europe.
3. That nonstop flights to the destination are how it will be done because connecting flights risks sightings at the connecting airport (note - World Race Productions has violated this many times, but I think that they design a first leg with one non-stop flight whenever possible).
4. That at least 2 flights from LAX to the destination within a 3 hour period are needed to get acceptable Amazing Race first flights (this is traditionally how World Race Productions designs Amazing Races).
5. That the first flight should be between 2pm and midnight (again, this is how World Race Productions designs Amazing Races).
6. The fact that some international flights are not daily should be ignored to cut down on complexity of the analysis.
7. The first flight will not be to the Caribbean, Central America, South America or Africa (this one is not difficult because there are no LAX to Africa nonstops that I am aware of). Since we know of several Amazing Races starting to Latin America, I know that this is frequently not a valid assumption, but you have to cut the complexity of the analysis somehow.
I went to Thursday's LAX list of departures to find out the following:
TO EUROPE FITTING MY HYPOTHESIS
CDG 2 flights around 4pm
LHR 5 flights around 4 pm or 6pm
LHR 2 flights around 8pm and 9pm
TO EUROPE NOT FITTING MY HYPOTHESIS
DXB 6pm (note - Dubai is not in Europe but since it is a major hub for connecting flights it is a logical place to go)
DME 6pm (surprise; it is to Moscow's second airport)
TO ASIA FITTING MY HYPOTHESIS
PVG flights at 2pm and 3pm
TPE flights at 3pm and 5pm
PVG two flights at 7pm
SYD - 2 flights at 10pm and 1 at 12am
MEL - 3 flights at 11pm and 1 at 12am
TO ASIA NOT FITTING MY HYPOTHESIS
NRT - 4pm
SIN - 9pm
AKL - 10pm
CAN - 11pm
ICN - 11pm
BNE - 12am
So, what does this mean? If the flight is headed to Europe, then London or Paris are the most logical destinations. London is my favorite as Amazing Races have only visited England in AR3 and AR17.
If the flight is headed to eastern Asia there are more possibilities. I would love to think that the undervisited destination of the Philippines would be the destination of choice, but the assumptions of my analysis make that unlikely. The logical destinations that fit the hypothesis are Shanghai, Taipei, Sydney or Melbourne. Melbourne has been least visited by a U.S. Amazing Race (so far, never).
Now, I believe that this approach is valid to statistically predict over a wide range of Amazing Races where the first destination point is. However, it would get really boring with all Amazing Races having first departures only to London, Paris, Shanghai, Taipei, Sydney or Melbourne. The criterion of nonstop flights is frequently ignored by World Race Productions as they do use some connecting flights, which opens up hundreds of cities in the target areas as potential first destinations. So you have to take this analysis for what it is, built on a chain of assumptions. If you change that assumption in particular of any other assumptions you get a situation typically too complex for reasonable conclusions.