For programatically creating banners in landscape mode

ADBannerView *adView = [[ADBannerView alloc] initWithFrame:CGRectZero];

adView.requiredContentSizeIdentifiers = [NSSet setWithObject:ADBannerContentSizeIdentifierLandscape];

adView.currentContentSizeIdentifier = ADBannerContentSizeIdentifierLandscape;

[self.view addSubview:adView];