If I use airplane mode with Wi-Fi, will it use my cellular data (iPhone 5c)?

I have a iPhone 5c on AT&T and I recently got a text saying i've used 90% of my cellular data and if I go over they will charge me. If I use airplane mode with Wi-Fi and use apps such as snapchat, Kik, Twitter… Will it be using my data up?

If not, how do I avoid using data but still be able to use these apps on my phone.

Firmly and categorically NO