[Zephyr] is an amazing Warframe to play casually. She can CC with her Tornadoes, zoom 30m unstaggered, and deflect bullets.
What sets [Zephyr] apart from other warframes is, other warframe needs to activate skills and have absurdly high Ability Strength to [Reach] desired damage potential, while [Zephyr] just needs to jump :D
There's math involved and I understand that 100% damage reduction does not mean you receive zero damage, but honestly, I never die in solo steelpaths so yeah.

BUILD EXPLANATION

[Zephyr] is super tanky and hits like a truck while she's airborne. Her passive grants 150% crit chance when airborne on all weapons. This include Primary, Secondary, and Melee such as glaives and Exodia Contagion Zaws!
100% Damage reduction while [Zephyr] is airborne when you use a polearm and install "[Boreal's Contempt]".
Double Umbral & [Adaptation] for survivability on the ground. Whether you like it or not, you can't be high all the time ;)
For Zephyr's damage showcase, I included pictures down below.

• Why is your ability strength bigger than other builds?
  Nourish! Extra viral damage is no joke, and also when 200 strength you will get 3x energy from any source! this includes and not limited to

1. Energy pizzas
2. Zenurik school
3. Energy orbs
4. Other Warframes' skills such as [Trinity]'s and Harrow's
   Imagine a single pizza grants you 300 energy, and Zenurik fills you up 3 times faster. Nourish is wild.

• Why Nourish? Why is there no [Primed Flow]?
  Extra viral damage, Viral explosion when enemies hits you, and HUGE ENERGY REGENERATION!!! With nourish, my team and I never run out of energy, and also don't underestimate viral damage bonus because it is huge. Protip, even if your weapon doesn't have viral damage, this skill will imbue your weapons with viral nonetheless, making it great if your weapons lacks slot or a bossing weapon with no viral.
  In terms of energy, [Zephyr] is not a caster warframe, and therefore, [Primed Flow] is super overkill. I did however use blue archon shards for just a little energy (Archon Shards is listed below). Having Nourish and 175% efficiency is more than enough.

• Other Builds have [Zephyr] with huge Ability Range. Why are yours smaller?
  Those other builds have no to little survivability, because they rely on Tornado's CC to stay alive. But since eximus and bosses aren't affected, The range is often overkill, and more often than not, kills you otherwise.
  On my build, 175% ability range is enough. 45m Tornado is big enough to suck up normal enemies.
  But! if you want more range, you can switch Adaptation with Overextended. Honestly wouldn't recommend because you gain less damage & energy bonus from nourish.

• Your Ability Duration is kinda small..
  Honestly, not much of an issue. With 175 efficiency and massive energy regeneration, I can recast anytime. This is a bit of a problem with her 3rd skill if you want to deflect bullets, but with 100% damage reduction, honestly I never used her 3rd unless I'm protecting defense objectives/ reviving teammates.
  IF you need more duration, you could change "Arcane Guardian" with "Molt Efficiency".

ARCHON SHARDS

• Tau Yellow : Energy at spawn x1
• Tau Blue : Energy pool x1

And that's it I believe! The following is just flex slot

• Tau Blue : Armor x1
• Tau Red : Ability Strength x1
• N/Tau Red : Ability Duration x1

These Archon shards will give [Zephyr] extra survivability and comfier energy pool.
If you follow my build, Her stats become :
Energy 300
Armor 300
Health 1275

Ability Duration 105
Ability Efficiency 175
Ability Range 175
Ability Strength 170 (+60 with maxed molt augment)

HOW I PLAY [Zephyr]

If you use Zenurik class, cast its first skill and then Nourish. Zenurik's 5 energy per second becomes 12 energy per second. The more you kill, this later becomes 15 energy per seconds. This of course extends to your teammates.
I personally use Unairu to strip bosses.

Weapons I use are non AOE weapons that deals crap ton of damage. I personally use [Nataruk] with no viral mods.
Secondary weapon is up to your preference, but a primer like [Epitaph] or [Kuva Nukor] is always a safe option. Another option is [Sporelacer] pistol for aoe damage.
and for melee of course, any polearm so I can slot "[Boreal's Contempt]". I personally use [Plague Kripath] with Exodia Contagion so I can snipe corpus' cameras.

Since your crit chance and survivability increase while airborne, 90% of your playtime will be on the air, sniping from above. If you're adept, bullet jump forward and hold 1 just about right above ground to hover. This is great for low ceiling areas.
Tornado is used when you're defending objectives, or you can't quite aim right. If you didn't know, you could just shoot the tornadoes to hit enemies within them. This includes bosses as well. Even if they're not CCed, when they're within 45m of the tornado, they will take damage.

With 175 efficiency and boosted energy intake, you can Hold 1 for as long as you want. Take advantage of this, especially while bossing. Fun fact, Lephantis and melee bosses can't hit midair objects :) Cast nourish every time you need more damage and/or more energy from orbs.

And that's just about it~ [Zephyr] is a very casual frame. If you want to deal massive damage while being quite literally Invulnerable midair, this is the Warframe for you.

[Nataruk] Damage (Steel Path)

[Plague Kripath] with Exodia Contagion Damage (Steel Path)