" Before the battle of Verdun, our activity was disturbed by frequent thunder-storms.
Nothing is more disagreeable for flying men than to have to fly through a thunderstorm. During the Battle at Somme, a whole English Flying Squadron was forced down behind our lines and became our prisoners of war, because they had all been surprised by a thunderstorm.
I had never yet made an attempt to get through thunder clouds, however I could not suppress my desire ' to make the experiment.'
During one whole day, thunder was in the air. But in order to look after various things, I had flown over to the nearby fortress of Metz.
I had an adventure during my return.
After visiting the aerodrome of Metz, I had intended to return to my own base, when an approaching thunderstorm became noticeable. As it approached from the north, its vertical clouds looked like a gigantic . . pitch-black wall.
Old, experienced pilots, there, urged me not to fly. However, I had promised to return to my base. I should have considered myself a coward if I had failed to come back because of a silly thunderstorm.
Therefore, I meant to try.
I was in the air when the rain began falling. I had to throw away my goggles, otherwise I should not have seen anything. The trouble was that I had to travel over the mountains of the Moselle, where the thunderstorm was now raging.
And as I rapidly approached the black cloud which reached down to the earth, I said to myself that probably I should be lucky to get through it.
As I flew at the lowest possible altitude, I was compelled absolutely to leap over
houses and trees with my machine.
Very soon . . I no longer knew where I was. The gale seized my machine as if it were a piece of paper and drove it along. My heart sank within me. I could not land among those hills.
I was compelled to go on.
I was surrounded by an inky blackness. Beneath me the trees bent down in the gale. Suddenly, I saw right in front of me a wooded hill. I could not avoid it. I was able to fly only in a straight line. My Albatross managed to avoid its trees. And now I had to quickly avoid every obstacle that I encountered.
My flight became a jumping competition.
Purely and simply. I had to jump over trees, villages, spires and steeples, for I had to keep within a few yards of the ground . . otherwise I should have seen nothing at all [ in the dark, obscuring rain and violence. ]
The lightning was playing around me. At that time I did not yet know that lightning cannot touch flying machines. I felt certain of my death for it seemed to me inevitable that the gale would throw me at any moment into a village or a forest. Had the motor stopped working I should have been done for.
Suddenly, I saw that on the horizon the darkness had become less thick. The thunderstorm had passed, over there. If I were able to get that far, I would be saved.
Concentrating all my energy, I steered towards the light. Suddenly I got out of the thundercloud. The rain was still falling in torrents, but still I felt . . saved.
In pouring rain, I landed at my aerodrome. Everyone had been waiting for me. Metz had reported my start and had told them that I had been swallowed up by a thunder cloud. Withstanding the dangers during my flight, I had experienced glorious moments . . and I now realize that it was all very beautiful. But I shall never again fly through a thunderstorm . .
. . unless the Fatherland should demand it. "
Source : Manfred von Richthofen's letters to his family
I think he hand flew the whole way.