Russia does not normally buy 5 advanced fighter jets every day, so their peace time military budget is not a relevant comparison. The numbers in the article als

Russia does not normally buy 5 advanced fighter jets every day, so their peace time military budget is not a relevant comparison. The numbers in the article also seem to include future costs that might be ammortized over 50 years or something. So in short: the numbers are just wild guesses, but not nonsensical.