If you will travel in local area by AIR, do you still require to carry passport if you are a foreigner?

I will submit my passport to the Spain consulate for application of visa and this means I can't carry my passport to travel by AIR. Is it necessary to have it or I could show the receiving copy from the Consulate as a proof in the airport. Pls. advise and thanks for your help.
I'm from Xiamen and need to travel to Beijing then back to Xiamen that's why I want to know if really require to carry the passport during the trip or a copy can help.Pls. help me to plan my trip. Thanks so much.
I will carry my passport from Xiamen to Beijing, then submit my passport to the Spain embassy in Beijing so that means back to Xiamen I don't have my passport anymore.Is the Beijing airport need to check my passport or a receipt from embassy is ok?

If ur already in the country I don't know that it matters but I would ask for a copy just in case.

Internal travelling mostly requires just a photo ID, but if you're a foreigner visiting (as opposed to living in) the country, it's best to carry your passport when you do travel.

If you have it, carry it.

I wouldn't leave anything to chance with these Idiots in this country....

TSA is a joke, and love to flex their muscle when ever they get the chance.....

Generally you don't need your passport for traveling within a country providing you have another acceptable photo ID with you. However, your question seems to suggest that you will be flying to Beijing?? You will definitely need your passport for that.