the old planes have side mirrors and rear view mirrors specially those who were used as fighter planes during the 1st and 2nd world wars. they used to see the rear portion if there are enemies at their backs. as time passes by and technology evolves. that was remove it is because sensors and radars were invented.
I thought the side mirrors were well supported because of strong wind force normally approached on it while the plane on travel.
Probably at least 75 N / square cm. load applied on side mirrors by wind force while the plane travels that may cause to destroy it.
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