Yes, you can use Airtel bonus airtime for calls, depending on the specific tariff plan you are on. For instance, plans like Airtel SmartConnect and TalkMore offer significant bonuses on recharges, which can be used for national and international calls. When you recharge, you receive bonus airtime that can be utilized for making calls, and the amount of bonus varies based on the recharge amount. For example, with the TalkMore plan, recharging N100 can yield a bonus of up to N500, which can be used for calls. However, it's essential to check the terms of your specific plan, as some bonuses may have restrictions on usage.