Strategy for achieving Romeo, Alpha, Delta (Fly over 5KM)?

Try using the gravity belt and the turbo booster.

With the gravity belt equipped its safest to fly about 3/4ths up the screen. The gravity belt helps with your reaction time: you'll be able to drop below high zappers pretty quickly. Then get back up to the 3/4ths level as soon as you are able. At that height you can jetpack above any mid-level zappers.

The turbo booster is useful because you're invulernable every time you hit a boost. Alternately you could try using the de-zapinator, but I didn't find it too helpful since it is unreliable.

It really just comes down to having split-second reaction times.

I use the Lucky Last, Freeze-o-matic, Final Blast and a Revive. Definitely keep 3/4th of the way up and try to collect tokens. I didn't use the final blast until I reached at least 4500. After using the blast I use a revive. The Lucky Last is so you have a better chance of getting a free revive or blast. Freeze-o-matic is there to get you some extra distance when you die.

It took me a bit but it worked.

The turbo boost is nice but unreliable, I recommend the Gravity Belt and the Air Barrys. Remember that frustrating moment where you couldn't possibly have risen high enough to dodge that Zapper? Air Barrys make your initial jump almost instant and give you very high mobility up and down. You can't always stay in the middle of the screen and I find the Air Barrys more consistently help compared to the Turbo Boost.

In addition, if you have the coins, a well timed Revive (heart) or bomb can be just what you need to get a few hundred more meters. Save them up (I always had a few because I was required to buy them for challenges) until you have a good opportunity.