I'm in the New York (persuade Jennifer Taks) mission which seems to cause problems to a number of people. I even started from scratch once already since walkthroughs talk about a launcher you could use to take down flying vehicles, so I wanted to go back and see if I could get one anywhere. I can't research it, I've picked up every single possible briefcase I've been able to in the game (I may have not persuaded every single scientist I've come across, because the game never says you'd benefit from doing that.)

This mission is IMPOSSIBLE (seriously, just prove me wrong. I've tried at least 5 different approaches for dozens of times but it seems the game won't let me complete the mission with any other method than using the launcher weapons I do not have - see below) to complete without a rocket launcher, but never in my life have I even seen such a weapon in the game.

The mission is hard enough to the point I've gotten to as it is, but the true problem is entering the compound where Jennifer Taks is found. There's a large number of police officers in there, not to mention several laser turrets which make quite short work of my agents as is. But the worst thing is there's a flying vehicle that appears when I've been in the area for a while, and the rifles won't be able to dispose of it quickly enough. Any other weapon is simply a worse option to use there.

There's a clone shield found on one disguised enemy agent on the map, and I can use it to enter the compound using one agent, but when I persuade Jennifer Taks, the officers suddenly seem to think it's completely alright to kill her, even though they still wouldn't attack my agent. My lone agent can't deal with all 5 officers so I could reach the flying vehicle, instead he gets killed in a couple of seconds.

Closest attempt I had was when I pretty much persuaded the whole city to follow me using the Persuadertron (for some reason, you can fit any number of people in a vehicle, so I had some fun watching around 100 people disappear into that tin can), stuffed them all into the vehicle and entered the compound, and just tried to act quickly. I ended up losing my agents when I entered the flying police vehicle in the compound (that you need to use to escape), but I noticed in the meanwhile that when the flying enemy vehicle is destroyed, it causes a larger explosion than such vehicles normally would. It feels at this point as if the developers of this game are mocking me.

I could try the "100 sheep" technique again, as my group is fairly powerful when I've armed the citizens with weapons left by the zounds of enemies in the beginning of the mission, but in that case it'll be impossible to leave the compound quickly enough, as when I'll have dozens of persuaded people with me, I'd have no way of knowing which one of them is Jennifer Taks so I could know when to take off.

This game got extremely hard extremely fast, so I want to believe there is a rocket launcher of some kind I could use to complete the mission. Why can't I get one (or preferably several) from anywhere?

Sometimes it feels like everybody else is playing a completely different game when talking about Syndicate Wars. I wish there was a save option at least :( Oh well, here's hoping to get some answers. I'll try completing the mission without a launcher in the meantime, and report here if I can find a way, so it might hopefully help someone else.

I suppose when one makes the effort to cry for help the troubles suddenly disappear! New York, I bid you farewell.

The solution was simply to overrun the compound with brutal force. I persuaded almost every citizen in town and the cops guarding the bank. It's a party at Taks' house and everyone's invited!

I armed everyone with the guns left on the ground by the operatives I killed. I had around 100 people surrounding my agents when I exited the vehicle inside the compound. I also used the bar on the side that makes your agents invincible (?) for its duration. Result: when the smoke had cleared I saw almost every citizen in the city dead before me, and only a few of the persuaded police officers had survived. For some reason I don't even know, the flying vehicle never appeared this time. I don't know if something I did earlier caused it - I killed all the nearby Zealots for their weapons, but the flying tank isn't one of theirs I think, so I can't guess why the flying vehicle never came. Sorry :( I promptly persuaded Taks and left the area.

There is still the question of the missing launcher weapon... I wonder if I can get one later?

A lot of walkthroughs have this error: they mention flying vehicle so they mention that those should be taken down with launchers. But they are not available yet in NY. AFAIR you'll get them in Cape Town

It seems I was able to research the launcher very soon after NY. It's a devastating weapon indeed, too bad pretty much half of the Zealots are using them against me now! I'm pretty sure the flying vehicle belonged to the Zealots, and there isn't one to be seen on the area itself - however, there are occupied tanks behind some walls that don't seem to do anything during the mission. I don't know why the vehicle didn't appear the last time.

Okay well I destroyed them anyway :)
Then I'm pretty sure I just used the wall hugging+LR rifle+shield tactic against it.

I noticed later that the game may hide reinforcements in the map that don't actually show in the map unless you go right next to them. In the Reykjavik mission (the one where they attempt to destroy the facility when you attack) I looked through the city and accidentally ran into a hidden Zealot vehicle and 5-6 Zealots. Made the rest of the mission a whole a lot easier...

I'm currently in Colombo, and things are getting pretty serious. This is the hardest game I've played for a longest time, but also incredibly addictive.

Well, here's the thing - even if you destroy those flying tanks in advance one will still appear after you enter the compound.