Yes it is a correct sentence
Preditorial in the snese that more than just the follwing
The first error is in bold text below:
<span>"... it was not until the start of the 1900s that scientific attempts are made to get a man off the ground under his own steam."
In the above sentence, the word "are" is in the incorrect verb tense. To be grammatically correct, the word "are" should be replaced by "were".
</span>The second error is in bold text below:
"<span>These bicycles-on-wheels might seem comical to today’s aeronauts, but in 1912 they are good enough to help Gabriel Poulain..."</span>
In the above sentence as well, the word "are" is in the incorrect verb tense. To be grammatically correct, the word "are" should be replaced by "were".
If the word ends in a vowel {a e i o u} and then an "o", you add -s.
If the word ends in a consonant, and then an "o", you add -s or -es.