The latter has always been my favourite, in any language. I love the orderly, logical systems that people create just to speak to each other. Learning numerous rules of grammar is so… satisfying, for the lack of a better word. It’s like learning to code: sure, you’re doing it by following the tutorials that the previous generations of learners have compiled for you, but once you truly grasp a certain concept, the gratification is immense.

Let’s take a look at the verb летéть (I am using the Latin é for my own convenience). Лететь means “to be flying, once or habitually”.

Once: птицы летят на юг - the birds are flying south.
Habitually: птицы осенью летят на юг - the birds fly south in the autumn.

It is an imperfective verb, like its brother летáть (again, Latin á). “Летать” differs just by one letter, and its meaning is also slighty different: “to be flying, regularly or randomly”.

Regularly: я часто летаю в Австрию - I often fly to Austria.
Randomly: ласточки летают - the swallows are flying around.

Look at that, I translated “летают” as “flying around”. One word became two. Here lies the beauty of the language (and the part that is usually called hard): what we may express as several words in English, becomes one in Russian. Especially when it comes to verbal affixes. Our old Russian teacher told us the very first day, “affixes will fuck you up”. Well, he didn’t say these exact words, but I, a Novocastrian boy, simplified it a bit. So let’s dive into that!

There are 16 verbal prefixes in Russian. Some of those prefixes have situational variations, but they still mean the same thing. We’ll use the familiar pair “лететь - летать”. “Лететь” with any prefix becomes perfective, “летать” stays imperfective. Why? Because fuck you, that’s why.

В-: влететь - to fly into; влетать - to be flying into. Generally, perfective and imperfective aspects of the same prefix mean the same thing (except, you know, one’s perfective and the other’s not). So I’ll just write “same in imperfective” from now on.

Вз-: взлететь - to take off; взлетать - same in imperfective.

Вы-: вылететь - to fly out of; вылетать - same in imperfective.

До-: долететь - to fly and reach; долетать - same in imperfective.

За-: залететь - to reach and fly behind (e.g., a cloud); залетать - same in imperfective. If I’m flying first and you’re flying behind me (following), “за-” is not needed because it’s a different scenario. Alternatively, “залететь” means “to get pregnant” in colloquial speech, just for shits and giggles.

На-: налететь - to fly and reach once; налетать - same in imperfective. And for this verb and a certain selection of other motion verbs, this also means suddenness. Pissed yourself yet?

От-: отлететь - to fly a short distance away from; отлетать - same in imperfective.

Пере-: перелететь - to fly over; перелетать - same in imperfective. “Перелетать над” (yes, the preposition is needed in most cases) can be replaced with “лететь над” because you deserve to suffer.

По-: полететь - to start flying; полетать - to be flying for a short time. Why are these different, Tim? Just to fuck with you, you silly bugger!

Под-: подлететь - to fly and reach but we’re not there yet; подлетать - same in imperfective. The whole idea of not being there yet makes this different from “долет(еть|ать)”.

При-: прилететь - to fly and reach and stop there; прилетать - same in imperfective. Also differs from “долет(еть|ать)” because maybe you have reached it, but perhaps you’ll continue flying, perhaps not. “Прилет(еть|ать)” implies that you won’t fly anywhere else, this is your final stop.

Про-: пролететь - to fly by or through; пролетать - same in imperfective. Metaphorically, these also mean “to fail at a task”, like an exam or something.

С-: слететь - to fly down from; слетать - same in imperfective. “Слетать”, as a bonus, also means “to fly there and back”, either literally or figuratively (like I’m sending you out to buy beer, and I want you to make haste).

У-: улететь - to fly and leave; улетать - same in imperfective. Note the difference from “отлет(еть|ать)”. This is final, Jim, pack your goddamn bags, мы улетаем отсюда нафиг. “Отлет…”, again, implies just a short distance.

You may count these and realise there are only 14 prefixes on the list. I applaud your basic arithmetic skills. I left two out, and for a good reason.

“Из-” implies an Action to end all Actions. “Побить” (to beat somebody up) is much weaker than “избить” (to outright fucking mess someone up). It’s not a very productive prefix, its uses are limited to a few verbs, and “лет(еть|ать)” is not one of them. However, in older literature you may encounter “излететь” in the sense of words leaving someone’s lips. Very poetic. No one talks this way now.

“Раз-” implies partition and division. When you’re cutting meat, “разрезать” is perfectly fine because it’s you acting upon an object. But if it’s a fighter wing separating in the sky, we must use “разлетаться” (suffix “-ся”) because these objects are acting upon themselves.

This is turning into the longest answer I’ve ever written. I won’t list and describe all the verbal suffixes. There aren’t too many, and they’re fairly regular. Just one, I promise.

Meet “-ива-/-ыва-”. It is a good productive suffix, it can be appended to perfective verbs without imperfective counterparts to turn them into imperfective. “Настоял” - “insisted (masculine)”; “настаивал” - “was insisting (masculine)”.

A curious thing about this suffix is that it used to be productive in another area. It was used to transform verbs into experiential aspect, like “used to” in English. Some of these forms are perfectly mainstream now: “хаживал” - “used to go somewhere”. Some are dialectal and rare: “бирывал” (from “брать” - “to take”) - “used to hunt some animal”. There are very few such forms left in modern Russian. But as a joke, this ancient, ossified suffix can be revived by anyone and appended to any verb to make a form which sounds wrong and strange to any fluent speaker, yet is perfectly correct:

“Я лётывал в Германию - I used to fly to Germany”. Highly colloquial, this form is used for humorous effect.

This is just two verbs. And I didn’t even talk about suffixes. This is why Russian is hard. I am lucky to have a natural affinity toward languages. I’d have given up a long time ago otherwise.