*Bag fee seen adding $70 million to year revenue

*Agreements reached to defer plane deliveries

*Shares up 6 pct to $19.92 per share

ATLANTA, July 10 (Reuters) - Alaska Air Group Inc (ALK.N: Quote, Profile, Research) said on Friday that a fee it began charging passengers this month for a first checked bag was expected to add $70 million or more to annual revenue.

The parent of Alaska Airlines and Horizon Air Industries also said in a filing with the U.S. Securities and Exchange Commission that the fee, which it began charging on July 7, was expected to add about $30 million in revenue for its second half.

The company's shares were up $1.12, or 6 percent, to $19.92 in morning trading.

In its investor update, Alaska Air also said it expects revenue per available seat mile (RASM) to be down 6 percent to 7 percent in the second quarter from a year earlier for Alaska Airlines.

The company added that a modification of Alaska Airlines' affinity card agreement with Bank of America (BAC.N: Quote, Profile, Research) was expected to result in about $15 million of incremental revenue that it expects to record for June, pending a final accounting review.

It said the impact of the card agreement change was not included in its RASM forecast.