I should have written self reference.
True.
Iron is the key atom in blood that lets it transport oxygen and gives it a metallic taste.
True.
Iron is also the key material in [some] radio antennas.
True, with a [slight] correction.
Iron reacts with radio waves converting the electromagnetic energy into an electric current that can be amplified.
True. However, your conclusion is false. The iron in blood is bound to a Heme group in a hemoglobin molecule, which isolates the iron from other iron atoms making it incapable of responding like a conductor. In particular, it is incapable of producing an induction current. Sorry. No dice.
Radio waves expand with distance losing their power density
Roughly OK, I will allow it.
however a metal surface will reflect microwaves and a curved metal surface can refocus the energy like a lens.
True. [Just one picky little thing: it is not necessary that they be "curved," just "closed" in some sense.]
Sitting inside an airliner with 300 people talking on their cell phones is a little like being inside a microwave oven.
No, it is not. In the first place, the ambient electromagnetic radiation would be present whether they were talking on their cell phones or not, so if the effect you are talking about could be observed, it would be frying people even if they weren't gabbing away on their cell phones. Second, the frequency for microwave ovens is not the same as for cell phones. Third, microwave ovens operate by forcing water molecules, which are dipoles, to undergo state transitions in their rotational energy eigenstates. Now, in addition to rotations, these molecules can also undergo vibrations, and electronic transitions. The vibrational states are too far apart to be excited by microwaves -- that is why microwave ovens are comparatively poor at defrosting -- because the water molecules in ice are not free to rotate and the vibrational eigenstates are too far apart. The electronic excitation states are even further apart and certainly cannot be excited by microwaves.
That is the background.
Now, this is the puzzling thing to scientists: we have always known that energies powerful enough to cause transition in electronic states can damage human tissue and genetic material. When the excitations are powerful enough some electrons may even be removed -- this is called ionizing radiation. But no one has believed that the rotational states of a molecule have enough energy to effect basic chemistry -- chemistry is essentially happening in the electronic modes. It is true that using microwave excitations can cause the water molecules in your body to rotate more quickly. It is true that the rotational kinetic energy can be transferred as translational energy in your tissues and cause heating. But the degree of heating we observe is too small to cause the changes people are talking about.
This incidentally is the best reason why your airplane theory fails: experimentally, it is clearly false. If the inside of an airplane were a waveguide as perfect and energetic as a microwave oven, people would be boiled in seconds. OK, you said, "a little like a microwave," so they would be boiled in a few hours, or at least the cabin would heat up. But it doesn't. Try an experiment: take a digital thermometer sometime and check the thing randomly as you talk on a cell phone. I'll betcha you will not see anything but the random errors in the thermometer as far as temperature changes go with your phone on and off. This is why we say, if a mechanism exists, we don't know what it could be. The microwaves have caused rapid transitions in our head-scratching eigenstates (for scientists, this takes very little energy to cause.)
This lack of effect will even be true if you try the experiment with your head in a microwave oven while you use the cell phone, provided your wife doesn't try to turn on the oven, as mine probably would.