The F-104 is a perfectly honest airplane. Make one mistake and it'll kill you.

...attributed to legendary Lockheed test pilot Tony LeVier

It may seem strange to non pilots to hear a trait like honesty attached to an inanimate object like an airplane. What's that all about?

Honesty in an airplane refers to its flying characteristics in a very subjective way. Each pilot's notion of what honesty means in a plane differs, according to his or her preferences and experience.

In general, though, an honest airplane is one that doesn't do anything lethally surprising. It should enter no dangerous or uncontrollable flight regime without warning.

Typically, as a pilot, one might encounter this sort of thing at or near the point of aerodynamic stalling. A stall in an airplane, you may remember, has nothing to do with the plane's engine, but is instead the point at which the smooth, lift-producing airflow over the top of the plane's wing becomes detached from the wing's upper surface, and enters a state of burbling turbulence. At this point, the plane is no longer in controlled flight. It is instead on a ballistic trajectory. You can provoke a stall by chopping the throttle to idle, and attempting to maintain level flight as the plane decelerates. For awhile it works just fine, though you find you must pull back on the stick more and more as the speed decreases. The nose goes higher and higher, though you are not gaining altitude. Finally, at some airspeed, the wing gives up, and you are no longer flying but falling.

Now, an honest airplane will give you warning before it does this, usually in the form of some sort of "buffet", or shaking. Imagine driving over a dirt road that has taken on "washboard" ruts. This is your cue to add power, lower the nose of the plane, or both. Also, onset of the full stall will occur on both wings simultaneously, so that the nose of the plane tends to drop straight down. A dishonest plane, by contrast, will give no such warning, and may tend to precipitate the stall on one wing before the other. One moment, you're flying just fine, straight and level, and the next you are plummeting and upside down!

You can also stall a plane at high speed - this is called an accelerated stall. Military and aerobatic pilots train for this situation frequently. You can be in a level, steeply banked turn at 300 miles an hour and still pull back the stick to the point where airflow separation occurs. An honest airplane, once again, will give you ample warning. A dishonest one won't, and will give you a fantastic tumbling roller-coaster ride as it departs.

Once stalled, a dishonest plane may enter a spin. A more dishonest one may enter a flat spin, that is very difficult to get out of. I hope you remembered to have several thousand feet of altitude when you initiated this maneuver. If you did, you'll probably be okay. If not, I hope you're in a military jet with a good ejection seat.

Should you ever take private flying lessons, which I hope you do because it is a priceless experience, your instructor will expend considerable effort demonstrating the stall condition, so that you can recognize it and recover safely. Your instructor will also teach you that there is one specific moment when you want to make the plane stall: immediately before touchdown during landings. Once again, with an honest airplane, this phenomenon will occur over both wings at the same time, ideally just at the moment of touchdown. A dishonest one may stall one wing first, which will suprise you by dropping that wing, so that you hit with one main landing gear first. This can be awkward and dangerous. Many WW II military aircraft, most famously the P-51 Mustang, exhibited this type of tendency, and demanded more than an average level of competence for safe landings.

Dishonest flying characteristics are not found only in the stall regime. Many late war combat aircraft, and early jet aircraft exhibited all sorts of dangerous and unpredictable traits as airflow around the aircraft approached or exceeded Mach 1. Control reversal was one such phenomenon - the airplane suddenly begins responding to control inputs in exactly the reverse way - you move the stick to the left to initiate a bank to the left, but the plane banks right instead. At high subsonic and supersonic speeds, some planes exhibited a phenomenon called proverse yaw, which was an oscillation that could increase in amplitude until the airplane was no longer under control. At high speeds, this often led to disintegration of the aircraft.

This sort of thing is the reason why so many streets at Edwards Air Force Base are named after test pilots. The lessons were literally paid for with blood. Chuck Yeager really did have stones the size of canteloupes.

As you might imagine, aerodynamicists have expended great efforts over the years towards improving the flying characterstics, or honesty factor, of new plane designs. There are all sorts of tricks that can be used for this. The North American T-2 "Buckeye" trainers I flew in the intermediate phase of my Navy flight training, for example, did not naturally exhibit a buffet before the onset of full stall. Therefore, the Buckeye came with a "pedal shaker", which was a vibrating motor attached to the left rudder pedal, set to kick in and thereby warn you when the aircraft approached the stall point. The T-28 Trojan prop trainers I flew in the earlier primary phase of training had a 6 inch section of angle-iron welded to the leading edge of the right wing, because without it the plane tended to stall left wing first due to the spiral airflow pattern generated by the propeller. The angle iron strip ensured that the stall initiated over the right wing at the same time as the left. Many airplanes are built with "washout" in the wings, which is a subtle "twist" of the wing as you proceed outward from root to tip. This ensures that the stall initiates over the inboard section of the wing first, instead over the outboard section where the ailerons are. You will therefore not lose total aileron control during a partial stall condition. You may have noticed that modern jet aircraft, especially military ones, tend to have large vertical stabilizing surfaces - indeed, planes such as the F-14, F-15, the Russian MiG 29 and SU 27 aircraft have two vertical stabilizers - to eliminate the lethal proverse yaw condition. Stiffer wings and carefully designed control surfaces eliminate the control reversal phenomenon on modern designs. These generally make most modern designs "honest" airplanes. (The F-14 still had a nasty, unrecoverable flat spin condition you could fall into, though.)

And the F-104? Well, Tony Levier later denied uttering the quote I've given at the top of this writeup. So maybe he didn't say it. He should have, though.