être (to be), avoir (to have) and aller (to go) are irregular verbs in any tense. Here are their endings for the future:

être

English	French
I will be	je serai
you will be	tu seras
he/she will be	il/elle sera
we will be	nous serons
you will be	vous serez
they will be	ils/elles seront

Examples

Je serai de retour à 16h.

I will be back at 4pm.

Vous serez sains et saufs.

You will be safe and sound.

avoir

English	French
I will have	j'aurai
you will have	tu auras
he/she will have	il/elle aura
we will have	nous aurons
you will have	vous aurez
they will have	ils/elles auront

Examples

Tu auras plein d'amis.

You will have lots of friends.

Nous aurons 3 enfants.

We will have 3 children.

aller

English	French
I will go	j'irai
you will go	tu iras
he/she will go	il/elle ira
we will go	nous irons
you will go	vous irez
they will go	ils/elles iront

Examples

L'été prochain, elle ira sur la Côte d'Azur.

Next summer, she will go to the French Riviera.

Ils iront au Stade de France.

They will go to the Stade de France.